anti bag6 Search Results


94
Bio-Techne corporation human/mouse/rat bat3/bag6 antibody
Human/Mouse/Rat Bat3/Bag6 Antibody, supplied by Bio-Techne corporation, used in various techniques. Bioz Stars score: 94/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
https://www.bioz.com/result/human/mouse/rat bat3/bag6 antibody/product/Bio-Techne corporation
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92
Atlas Antibodies anti bag6 ab
Anti Bag6 Ab, supplied by Atlas Antibodies, used in various techniques. Bioz Stars score: 92/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
https://www.bioz.com/result/anti bag6 ab/product/Atlas Antibodies
Average 92 stars, based on 1 article reviews
anti bag6 ab - by Bioz Stars, 2026-02
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86
Creative BioMart bag6
Figure 4. USP13 interacts with the <t>Bag6</t> complex. (A) Endogenous interaction of USP13 with the Bag6 complex. Extracts from cells were subject to IP by the indicated antibodies followed by immunoblotting. (B) USP13 binds gp78 and Bag6 independent of its DUB activity. Extracts from HEK293 cells-transfected with the indicated plasmids Figure 4. Continued on next page
Bag6, supplied by Creative BioMart, used in various techniques. Bioz Stars score: 86/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
https://www.bioz.com/result/bag6/product/Creative BioMart
Average 86 stars, based on 1 article reviews
bag6 - by Bioz Stars, 2026-02
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90
Abnova anti-bag6
MAVS is a high-confidence proximal interactor of SGTA. (A) Left, schematic of human SGTA–BioID2–HA displaying its protein–protein interaction modules. UBLbd, N-terminal domain that binds to the ubiquitin-like (UBL) domains of Ubl4A and <t>Bag6;</t> TPRd, central tetratricopeptide repeat (TPR) domain that interacts with heat-shock proteins; substratebd (sub/tebd), C-terminal domain that contains the hydrophobic substrate-binding site. Right, schematics of the SGTA–BioID2 mutants and respective disrupted interactions. Mutated amino acids are indicated. (B) Scheme for the BioID2-mediated proximity labelling and identification of SGTA substrates and cofactors using SGTA KO cells (see Fig. S1 ) transiently expressing wild-type (wt) SGTA-BioID2 or mutant variants shown in A. Cells expressing Myc–BioID2 or PEX19–BioID2 serve as two independent controls to exclude non-specific interactors. (C) Heat map representing log2-transformed fold changes in the protein intensities of significant (BFDR<0.05) wild-type (wt)/mutant SGTA-specific preys relative to both the Myc–BioID2 and PEX19–BioID2 controls. Individual rounded values are depicted in the heat map. A non-significant prey is shown as a white box (three biological replicates; see Tables S1–S3 for list of all proteins detected). (D) Validation of selected SGTA-associated candidates from C by immunoblotting. SGTA KO cells expressing the indicated BioID2-tagged baits were treated with biotin for 8 h and lysed with RIPA buffer. The resulting extracts were subjected to affinity purification with streptavidin beads and the bound material eluted using a biotin-containing buffer. The input and eluted material were analysed by immunoblotting for the indicated endogenous proteins. Stx-5 can be observed as two bands (indicated by arrows) corresponding to two isoforms, a 42 kDa-ER and a 35 kDa-Golgi isoform that result from an alternative initiation of translation . Blots representative of three independent biological replicates.
Anti Bag6, supplied by Abnova, used in various techniques. Bioz Stars score: 90/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
https://www.bioz.com/result/anti-bag6/product/Abnova
Average 90 stars, based on 1 article reviews
anti-bag6 - by Bioz Stars, 2026-02
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90
Beijing Solarbio Science anti-bag6 antibody cat#k112847p
DERL2 interacting with <t>BAG6.</t> A Schematic flow chart of the experimental design. B 293T cells were transfected with the Flag-DERL2 or/and HA-BAG6 vectors. Forty-eight hours later, the immunoprecipitated complex with Anti-HA beads was analyzed using the corresponding antibodies. C 293T cells were transfected with the Flag- DERL2 or/and HA- BAG6 vectors. Forty-eight hours later, the immunoprecipitated complex with anti-Flag beads was analyzed using the corresponding antibodies. D Fluorescence confocal microscopy analysis of the colocalization of DERL2 with BAG6 in the QBC939 cells transfected with. Flag- DERL2 or/and HA- BAG6 vectors. E Western blot analysis of BAG6 expression in the QBC939 cells upon DERL2 depletion or not. Significance: *** p < 0.001. F Western blot analysis of BAG6 expression in the QBC939 cells transfected the increased dose of Flag- DERL2 vectors. G Western blot analysis of BAG6 expression in the BAG6-overexpressing QBC939 cells transfected with Flag- DERL2 vectors or not. Forty-eight hours later, Chx was added. At different times later, Flag/HA antibodies were used to detect the DERL2 or BAG6 expression
Anti Bag6 Antibody Cat#K112847p, supplied by Beijing Solarbio Science, used in various techniques. Bioz Stars score: 90/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
https://www.bioz.com/result/anti-bag6 antibody cat#k112847p/product/Beijing Solarbio Science
Average 90 stars, based on 1 article reviews
anti-bag6 antibody cat#k112847p - by Bioz Stars, 2026-02
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90
Peptide Specialty Laboratories anti-bag6 rabbit polyclonal antibodies
MAVS is a high-confidence proximal interactor of SGTA. (A) Left, schematic of human SGTA–BioID2–HA displaying its protein–protein interaction modules. UBLbd, N-terminal domain that binds to the ubiquitin-like (UBL) domains of Ubl4A and <t>Bag6;</t> TPRd, central tetratricopeptide repeat (TPR) domain that interacts with heat-shock proteins; substratebd (sub/tebd), C-terminal domain that contains the hydrophobic substrate-binding site. Right, schematics of the SGTA–BioID2 mutants and respective disrupted interactions. Mutated amino acids are indicated. (B) Scheme for the BioID2-mediated proximity labelling and identification of SGTA substrates and cofactors using SGTA KO cells (see Fig. S1 ) transiently expressing wild-type (wt) SGTA-BioID2 or mutant variants shown in A. Cells expressing Myc–BioID2 or PEX19–BioID2 serve as two independent controls to exclude non-specific interactors. (C) Heat map representing log2-transformed fold changes in the protein intensities of significant (BFDR<0.05) wild-type (wt)/mutant SGTA-specific preys relative to both the Myc–BioID2 and PEX19–BioID2 controls. Individual rounded values are depicted in the heat map. A non-significant prey is shown as a white box (three biological replicates; see Tables S1–S3 for list of all proteins detected). (D) Validation of selected SGTA-associated candidates from C by immunoblotting. SGTA KO cells expressing the indicated BioID2-tagged baits were treated with biotin for 8 h and lysed with RIPA buffer. The resulting extracts were subjected to affinity purification with streptavidin beads and the bound material eluted using a biotin-containing buffer. The input and eluted material were analysed by immunoblotting for the indicated endogenous proteins. Stx-5 can be observed as two bands (indicated by arrows) corresponding to two isoforms, a 42 kDa-ER and a 35 kDa-Golgi isoform that result from an alternative initiation of translation . Blots representative of three independent biological replicates.
Anti Bag6 Rabbit Polyclonal Antibodies, supplied by Peptide Specialty Laboratories, used in various techniques. Bioz Stars score: 90/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
https://www.bioz.com/result/anti-bag6 rabbit polyclonal antibodies/product/Peptide Specialty Laboratories
Average 90 stars, based on 1 article reviews
anti-bag6 rabbit polyclonal antibodies - by Bioz Stars, 2026-02
90/100 stars
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Image Search Results


Figure 4. USP13 interacts with the Bag6 complex. (A) Endogenous interaction of USP13 with the Bag6 complex. Extracts from cells were subject to IP by the indicated antibodies followed by immunoblotting. (B) USP13 binds gp78 and Bag6 independent of its DUB activity. Extracts from HEK293 cells-transfected with the indicated plasmids Figure 4. Continued on next page

Journal: eLife

Article Title: USP13 antagonizes gp78 to maintain functionality of a chaperone in ER-associated degradation

doi: 10.7554/elife.01369

Figure Lengend Snippet: Figure 4. USP13 interacts with the Bag6 complex. (A) Endogenous interaction of USP13 with the Bag6 complex. Extracts from cells were subject to IP by the indicated antibodies followed by immunoblotting. (B) USP13 binds gp78 and Bag6 independent of its DUB activity. Extracts from HEK293 cells-transfected with the indicated plasmids Figure 4. Continued on next page

Article Snippet: Other antibodies used are FLAG (M2) (Sigma, St. Louis, MO), p97 (Fitzgerald, Acton, MA), UBE1 (Sigma), UbxD8 (Proteintech Group, Chicago, IL), Myc (Santa Cruz, Dallas, TX), Trc35 (Novus Biologicals, Littleton, CO), ubiquitin (P4D1, Santa Cruz), Bag6 (Creative BioMart, Shirley, NY), PDI (1D3), Hsp90 (AC88) (Enzo Life Sciences, Farmingdale, NY), and MMS1 (BIOMOL/Enzo, Farmingdale, NY).

Techniques: Western Blot, Activity Assay, Transfection

Figure 7. Hyper-ubiquitination of Ubl4A is associated with Bag6 clipping and ERAD inhibition. (A) Membrane-associated Bag6 is preferentially cleaved in USP13 knockdown cells. C, cytosol fraction; M, membrane fraction. (B and C) Overexpression of gp78 causes cleavage of Bag6. (B) A fraction of the cells transfected as indicated were extracted sequentially with NP40- and SDS-containing buffers. The corresponding extracts were analyzed by immunoblotting. (C) Protein extracts from HEK293 cells transfected with control or gp78-expressing plasmid were subject to immunoprecipitation with Ubl4A antibodies or with IgG as a negative control. (D) Overexpression of a Ub-Ubl4A fusion protein induces Bag6 cleavage. As in B, except that cells expressing the indicated proteins were analyzed. (E) Overexpression of wild-type gp78 inhibits TCRα degradation. The number indicates the relative levels of TCRα averaged from two independent experiments. (F) Overexpression of Ub-Ubl4A inhibits TCRα degradation. The graph shows the quantification results from three independent experiments. Error bars, SD (n = 3). DOI: 10.7554/eLife.01369.013

Journal: eLife

Article Title: USP13 antagonizes gp78 to maintain functionality of a chaperone in ER-associated degradation

doi: 10.7554/elife.01369

Figure Lengend Snippet: Figure 7. Hyper-ubiquitination of Ubl4A is associated with Bag6 clipping and ERAD inhibition. (A) Membrane-associated Bag6 is preferentially cleaved in USP13 knockdown cells. C, cytosol fraction; M, membrane fraction. (B and C) Overexpression of gp78 causes cleavage of Bag6. (B) A fraction of the cells transfected as indicated were extracted sequentially with NP40- and SDS-containing buffers. The corresponding extracts were analyzed by immunoblotting. (C) Protein extracts from HEK293 cells transfected with control or gp78-expressing plasmid were subject to immunoprecipitation with Ubl4A antibodies or with IgG as a negative control. (D) Overexpression of a Ub-Ubl4A fusion protein induces Bag6 cleavage. As in B, except that cells expressing the indicated proteins were analyzed. (E) Overexpression of wild-type gp78 inhibits TCRα degradation. The number indicates the relative levels of TCRα averaged from two independent experiments. (F) Overexpression of Ub-Ubl4A inhibits TCRα degradation. The graph shows the quantification results from three independent experiments. Error bars, SD (n = 3). DOI: 10.7554/eLife.01369.013

Article Snippet: Other antibodies used are FLAG (M2) (Sigma, St. Louis, MO), p97 (Fitzgerald, Acton, MA), UBE1 (Sigma), UbxD8 (Proteintech Group, Chicago, IL), Myc (Santa Cruz, Dallas, TX), Trc35 (Novus Biologicals, Littleton, CO), ubiquitin (P4D1, Santa Cruz), Bag6 (Creative BioMart, Shirley, NY), PDI (1D3), Hsp90 (AC88) (Enzo Life Sciences, Farmingdale, NY), and MMS1 (BIOMOL/Enzo, Farmingdale, NY).

Techniques: Ubiquitin Proteomics, Inhibition, Membrane, Knockdown, Over Expression, Transfection, Western Blot, Control, Expressing, Plasmid Preparation, Immunoprecipitation, Negative Control

Figure 8. USP13 maintains a functional interaction between Bag6 and SGTA. (A) Lys48 of Ubl4A is required for gp78-mediated ubiquitination in cells. Cells stably expressing wild type and K48R mutant Ubl4A were transfected with either an empty vector (control) or a gp78-expressing vector. Whole cell extracts were either directly analyzed Figure 8. Continued on next page

Journal: eLife

Article Title: USP13 antagonizes gp78 to maintain functionality of a chaperone in ER-associated degradation

doi: 10.7554/elife.01369

Figure Lengend Snippet: Figure 8. USP13 maintains a functional interaction between Bag6 and SGTA. (A) Lys48 of Ubl4A is required for gp78-mediated ubiquitination in cells. Cells stably expressing wild type and K48R mutant Ubl4A were transfected with either an empty vector (control) or a gp78-expressing vector. Whole cell extracts were either directly analyzed Figure 8. Continued on next page

Article Snippet: Other antibodies used are FLAG (M2) (Sigma, St. Louis, MO), p97 (Fitzgerald, Acton, MA), UBE1 (Sigma), UbxD8 (Proteintech Group, Chicago, IL), Myc (Santa Cruz, Dallas, TX), Trc35 (Novus Biologicals, Littleton, CO), ubiquitin (P4D1, Santa Cruz), Bag6 (Creative BioMart, Shirley, NY), PDI (1D3), Hsp90 (AC88) (Enzo Life Sciences, Farmingdale, NY), and MMS1 (BIOMOL/Enzo, Farmingdale, NY).

Techniques: Functional Assay, Ubiquitin Proteomics, Stable Transfection, Expressing, Mutagenesis, Transfection, Plasmid Preparation, Control

MAVS is a high-confidence proximal interactor of SGTA. (A) Left, schematic of human SGTA–BioID2–HA displaying its protein–protein interaction modules. UBLbd, N-terminal domain that binds to the ubiquitin-like (UBL) domains of Ubl4A and Bag6; TPRd, central tetratricopeptide repeat (TPR) domain that interacts with heat-shock proteins; substratebd (sub/tebd), C-terminal domain that contains the hydrophobic substrate-binding site. Right, schematics of the SGTA–BioID2 mutants and respective disrupted interactions. Mutated amino acids are indicated. (B) Scheme for the BioID2-mediated proximity labelling and identification of SGTA substrates and cofactors using SGTA KO cells (see Fig. S1 ) transiently expressing wild-type (wt) SGTA-BioID2 or mutant variants shown in A. Cells expressing Myc–BioID2 or PEX19–BioID2 serve as two independent controls to exclude non-specific interactors. (C) Heat map representing log2-transformed fold changes in the protein intensities of significant (BFDR<0.05) wild-type (wt)/mutant SGTA-specific preys relative to both the Myc–BioID2 and PEX19–BioID2 controls. Individual rounded values are depicted in the heat map. A non-significant prey is shown as a white box (three biological replicates; see Tables S1–S3 for list of all proteins detected). (D) Validation of selected SGTA-associated candidates from C by immunoblotting. SGTA KO cells expressing the indicated BioID2-tagged baits were treated with biotin for 8 h and lysed with RIPA buffer. The resulting extracts were subjected to affinity purification with streptavidin beads and the bound material eluted using a biotin-containing buffer. The input and eluted material were analysed by immunoblotting for the indicated endogenous proteins. Stx-5 can be observed as two bands (indicated by arrows) corresponding to two isoforms, a 42 kDa-ER and a 35 kDa-Golgi isoform that result from an alternative initiation of translation . Blots representative of three independent biological replicates.

Journal: Journal of Cell Science

Article Title: Mitochondrial antiviral-signalling protein is a client of the BAG6 protein quality control complex

doi: 10.1242/jcs.259596

Figure Lengend Snippet: MAVS is a high-confidence proximal interactor of SGTA. (A) Left, schematic of human SGTA–BioID2–HA displaying its protein–protein interaction modules. UBLbd, N-terminal domain that binds to the ubiquitin-like (UBL) domains of Ubl4A and Bag6; TPRd, central tetratricopeptide repeat (TPR) domain that interacts with heat-shock proteins; substratebd (sub/tebd), C-terminal domain that contains the hydrophobic substrate-binding site. Right, schematics of the SGTA–BioID2 mutants and respective disrupted interactions. Mutated amino acids are indicated. (B) Scheme for the BioID2-mediated proximity labelling and identification of SGTA substrates and cofactors using SGTA KO cells (see Fig. S1 ) transiently expressing wild-type (wt) SGTA-BioID2 or mutant variants shown in A. Cells expressing Myc–BioID2 or PEX19–BioID2 serve as two independent controls to exclude non-specific interactors. (C) Heat map representing log2-transformed fold changes in the protein intensities of significant (BFDR<0.05) wild-type (wt)/mutant SGTA-specific preys relative to both the Myc–BioID2 and PEX19–BioID2 controls. Individual rounded values are depicted in the heat map. A non-significant prey is shown as a white box (three biological replicates; see Tables S1–S3 for list of all proteins detected). (D) Validation of selected SGTA-associated candidates from C by immunoblotting. SGTA KO cells expressing the indicated BioID2-tagged baits were treated with biotin for 8 h and lysed with RIPA buffer. The resulting extracts were subjected to affinity purification with streptavidin beads and the bound material eluted using a biotin-containing buffer. The input and eluted material were analysed by immunoblotting for the indicated endogenous proteins. Stx-5 can be observed as two bands (indicated by arrows) corresponding to two isoforms, a 42 kDa-ER and a 35 kDa-Golgi isoform that result from an alternative initiation of translation . Blots representative of three independent biological replicates.

Article Snippet: Other antibodies used were as follows: anti-ATP13A1 (Proteintech 16244-1-AP, Lot 00007441; 1:2500 for IB), anti-Bag6 (Abnova H00007917-B01P, Lot J9271; 1:5000 for IB), anti-calnexin (Cell Signaling Technology #2679, Lot 4; 1:1000 for IB), anti-EMC1 (Abgent AP10226b, Lot SA100702BL; 1:500 for IB), anti-EMC2 (Santa Cruz Biotechnology sc-166011; 1:500 for IB), anti-EMC5 (Bethyl Laboratories A305-832A-M; 1:1000 for IB), anti-HA [Covance MMS-101R, Lot 14811501; 1:1000 for IB; 1:500 for immunofluorescence (IF)], anti-His (Sigma H1029, Lot 106M4768V; 1:3000 for IB), anti-Hsp70 (Abcam ab47455, Lot GR166016-49; 1:5000 for IB), anti-Hsp90 (Enzo Life Sciences ADI-SPA-846, Lot 07061528; 1:2000 for IB), anti-IRF3 (Cell Signaling Technology #11904, Lot 6; 1:1000 for IB), anti-phospho-IRF3 (Cell Signaling Technology #4947, Lot 13; 1:1000 for IB), anti-MAVS (Santa Cruz Biotechnology sc-166583, Lot L3119 and Lot C0421; 1:1000 for IB), anti-MAVS (Enzo Life Sciences ALX-210-929-C100, Lot 08061948; 1:100 for IP), anti-Myc (Merck Millipore 05-724, Lot 3095953; 1:5000 for IB), anti-Myc (Cell Signaling Technology #2276, Lot 24; 1:2000 for IF), anti-OMP25 (Proteintech 15666-1-AP, Lot 00068490; 1:1000 for IB), anti-OST48 [previously described ( ); 1:1000 for IB], anti-SGTA (Santa Cruz Biotechnology sc-130557, Lot E0809; 1:500 for IB), anti-Stx-5 (Synaptic Systems 110053, Lot 1-18 and Lot 110053/15; 1:5000 for IB, 1:100 for IP), anti-Stx-5 (Santa Cruz Biotechnology sc-365124, Lot H1419; 1:500 for IB), anti-TOM20 (Santa Cruz Biotechnology sc-17764, Lot H0320; 1:500 for IB), anti-TRC35 (Bethyl Laboratories A302-613A, Lot 1; 1:1000 for IB), anti-tubulin (gift from Keith Gull, University of Oxford, UK; 1:1000 for IB), anti-ubiquilin (Invitrogen 37-7700, Lot RJ241978; 1:1000 for IB), anti-ubiquilin-2 (Abcam ab217056, Lot GR3185004-6; 1:2000 for IB, 1:100 for IP), anti-rabbit IgG (Santa Cruz Biotechnology sc-2027, Lot F2413; 1:40 for IP) and anti-chicken IgY (Santa Cruz Biotechnology sc-2718, Lot L1412; 1:40 for IP).

Techniques: Binding Assay, Expressing, Mutagenesis, Transformation Assay, Western Blot, Affinity Purification

SGTA interacts with MAVS. (A) A cytosolic pool of endogenous MAVS can be observed at steady-state. Top, schematic of subcellular fractionation protocol used to separate the cell homogenate into crude cytosolic supernatant (S) and membrane-associated pellet (P) fractions. Bottom, detergent-free extracts from control KO cells (see Fig. S1 ) were fractionated as shown above. Equivalent amounts of each fraction were analysed by immunoblotting for MAVS and various compartmental markers. Bag6, SGTA and tubulin (cytosolic markers), TOM20 (mitochondrial outer membrane marker) and calnexin (CNX, ER membrane marker) serve as fractionation controls. Note that the MAVS-specific antibody, raised against amino acids 1–135 of human MAVS, detected the ∼80 kDa full-length MAVS (marked by an arrow) and multiple shorter variants that most likely represent C-terminally degraded products or processed forms of the full-length protein (see also ). Quantification of the levels of full-length MAVS recovered in the cytosolic fraction is indicated below the MAVS blot. Value represents mean±s.e.m. from three independent experiments. (B) MAVS co-immunoprecipitates with SGTA. The supernatant (S) fraction from A was subjected to immunoprecipitations with equal amounts of chicken anti-SGTA antibody (αSGTA) or chicken IgY antibody (control for non-specific binding). Input and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. Bag6 served as positive control for SGTA binding. In A and B, arrows next to the Stx-5 blots indicate the two Stx-5 isoforms. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. Blots representative of three independent experiments. (C) In vitro translated MAVS interacts with recombinant SGTA via its transmembrane domain (TMD). Top, schematic of FLAG–MAVS displaying its N-terminal caspase activation and recruitment domain (CARD) and C-terminal TMD. Bottom, FLAG-MAVS full-length, ΔCARD or ΔTMD truncated variants were translated in vitro in the absence or presence (+) of 2 µM His-S-tag-SGTA. A 10% sample of the total translation products was subjected to denaturing immunoprecipitations with anti-FLAG antibody (totals), while the rest was incubated with HisPur cobalt resin and bound proteins were eluted using imidazole (eluates). Totals and eluates were resolved by SDS-PAGE and results visualised by phosphorimaging. Downward arrows indicate full-length and ΔCARD FLAG–MAVS selectively bound by His-S-tag-SGTA. His-S-tag-SGTA and its binding partners within rabbit reticulocyte lysate were released from the resin by incubating the beads with SDS sample buffer (beads) and samples were analysed by immunoblotting (IB). The anti-His and anti-Bag6 immunoblots indicate uniform binding of Bag6 binding-competent His-S-tag-SGTA to beads. Results shown in C are representative of two independent experiments.

Journal: Journal of Cell Science

Article Title: Mitochondrial antiviral-signalling protein is a client of the BAG6 protein quality control complex

doi: 10.1242/jcs.259596

Figure Lengend Snippet: SGTA interacts with MAVS. (A) A cytosolic pool of endogenous MAVS can be observed at steady-state. Top, schematic of subcellular fractionation protocol used to separate the cell homogenate into crude cytosolic supernatant (S) and membrane-associated pellet (P) fractions. Bottom, detergent-free extracts from control KO cells (see Fig. S1 ) were fractionated as shown above. Equivalent amounts of each fraction were analysed by immunoblotting for MAVS and various compartmental markers. Bag6, SGTA and tubulin (cytosolic markers), TOM20 (mitochondrial outer membrane marker) and calnexin (CNX, ER membrane marker) serve as fractionation controls. Note that the MAVS-specific antibody, raised against amino acids 1–135 of human MAVS, detected the ∼80 kDa full-length MAVS (marked by an arrow) and multiple shorter variants that most likely represent C-terminally degraded products or processed forms of the full-length protein (see also ). Quantification of the levels of full-length MAVS recovered in the cytosolic fraction is indicated below the MAVS blot. Value represents mean±s.e.m. from three independent experiments. (B) MAVS co-immunoprecipitates with SGTA. The supernatant (S) fraction from A was subjected to immunoprecipitations with equal amounts of chicken anti-SGTA antibody (αSGTA) or chicken IgY antibody (control for non-specific binding). Input and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. Bag6 served as positive control for SGTA binding. In A and B, arrows next to the Stx-5 blots indicate the two Stx-5 isoforms. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. Blots representative of three independent experiments. (C) In vitro translated MAVS interacts with recombinant SGTA via its transmembrane domain (TMD). Top, schematic of FLAG–MAVS displaying its N-terminal caspase activation and recruitment domain (CARD) and C-terminal TMD. Bottom, FLAG-MAVS full-length, ΔCARD or ΔTMD truncated variants were translated in vitro in the absence or presence (+) of 2 µM His-S-tag-SGTA. A 10% sample of the total translation products was subjected to denaturing immunoprecipitations with anti-FLAG antibody (totals), while the rest was incubated with HisPur cobalt resin and bound proteins were eluted using imidazole (eluates). Totals and eluates were resolved by SDS-PAGE and results visualised by phosphorimaging. Downward arrows indicate full-length and ΔCARD FLAG–MAVS selectively bound by His-S-tag-SGTA. His-S-tag-SGTA and its binding partners within rabbit reticulocyte lysate were released from the resin by incubating the beads with SDS sample buffer (beads) and samples were analysed by immunoblotting (IB). The anti-His and anti-Bag6 immunoblots indicate uniform binding of Bag6 binding-competent His-S-tag-SGTA to beads. Results shown in C are representative of two independent experiments.

Article Snippet: Other antibodies used were as follows: anti-ATP13A1 (Proteintech 16244-1-AP, Lot 00007441; 1:2500 for IB), anti-Bag6 (Abnova H00007917-B01P, Lot J9271; 1:5000 for IB), anti-calnexin (Cell Signaling Technology #2679, Lot 4; 1:1000 for IB), anti-EMC1 (Abgent AP10226b, Lot SA100702BL; 1:500 for IB), anti-EMC2 (Santa Cruz Biotechnology sc-166011; 1:500 for IB), anti-EMC5 (Bethyl Laboratories A305-832A-M; 1:1000 for IB), anti-HA [Covance MMS-101R, Lot 14811501; 1:1000 for IB; 1:500 for immunofluorescence (IF)], anti-His (Sigma H1029, Lot 106M4768V; 1:3000 for IB), anti-Hsp70 (Abcam ab47455, Lot GR166016-49; 1:5000 for IB), anti-Hsp90 (Enzo Life Sciences ADI-SPA-846, Lot 07061528; 1:2000 for IB), anti-IRF3 (Cell Signaling Technology #11904, Lot 6; 1:1000 for IB), anti-phospho-IRF3 (Cell Signaling Technology #4947, Lot 13; 1:1000 for IB), anti-MAVS (Santa Cruz Biotechnology sc-166583, Lot L3119 and Lot C0421; 1:1000 for IB), anti-MAVS (Enzo Life Sciences ALX-210-929-C100, Lot 08061948; 1:100 for IP), anti-Myc (Merck Millipore 05-724, Lot 3095953; 1:5000 for IB), anti-Myc (Cell Signaling Technology #2276, Lot 24; 1:2000 for IF), anti-OMP25 (Proteintech 15666-1-AP, Lot 00068490; 1:1000 for IB), anti-OST48 [previously described ( ); 1:1000 for IB], anti-SGTA (Santa Cruz Biotechnology sc-130557, Lot E0809; 1:500 for IB), anti-Stx-5 (Synaptic Systems 110053, Lot 1-18 and Lot 110053/15; 1:5000 for IB, 1:100 for IP), anti-Stx-5 (Santa Cruz Biotechnology sc-365124, Lot H1419; 1:500 for IB), anti-TOM20 (Santa Cruz Biotechnology sc-17764, Lot H0320; 1:500 for IB), anti-TRC35 (Bethyl Laboratories A302-613A, Lot 1; 1:1000 for IB), anti-tubulin (gift from Keith Gull, University of Oxford, UK; 1:1000 for IB), anti-ubiquilin (Invitrogen 37-7700, Lot RJ241978; 1:1000 for IB), anti-ubiquilin-2 (Abcam ab217056, Lot GR3185004-6; 1:2000 for IB, 1:100 for IP), anti-rabbit IgG (Santa Cruz Biotechnology sc-2027, Lot F2413; 1:40 for IP) and anti-chicken IgY (Santa Cruz Biotechnology sc-2718, Lot L1412; 1:40 for IP).

Techniques: Fractionation, Membrane, Control, Western Blot, Marker, Binding Assay, Positive Control, Derivative Assay, In Vitro, Recombinant, Activation Assay, Incubation, SDS Page

Bag6 interacts with MAVS. (A) MAVS co-immunoprecipitates with Bag6. Control KO cells were fractionated as shown in <xref ref-type=Fig. 2A and the supernatant (S) fraction was subjected to immunoprecipitations with equal amounts of rabbit anti-Bag6 antibody (αBag6) or rabbit IgG antibody (control for non-specific binding). Input and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as positive control for Bag6 binding. (B) SGTA facilitates Bag6–MAVS interaction. Control KO and SGTA KO cells were fractionated as shown in Fig. 2A and the supernatant (S) fractions were subjected to immunoprecipitations with rabbit anti-Bag6 antibody (αBag6) or rabbit control IgG antibody. Inputs and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as positive control for Bag6 binding. Arrow in A and B indicates full-length MAVS. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. (C) Mean±s.e.m. of MAVS levels that co-immunoprecipitate with Bag6 in control KO and SGTA KO cells for three independent experiments as in B. * P <0.05 (unpaired two-tailed t -test). " width="100%" height="100%">

Journal: Journal of Cell Science

Article Title: Mitochondrial antiviral-signalling protein is a client of the BAG6 protein quality control complex

doi: 10.1242/jcs.259596

Figure Lengend Snippet: Bag6 interacts with MAVS. (A) MAVS co-immunoprecipitates with Bag6. Control KO cells were fractionated as shown in Fig. 2A and the supernatant (S) fraction was subjected to immunoprecipitations with equal amounts of rabbit anti-Bag6 antibody (αBag6) or rabbit IgG antibody (control for non-specific binding). Input and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as positive control for Bag6 binding. (B) SGTA facilitates Bag6–MAVS interaction. Control KO and SGTA KO cells were fractionated as shown in Fig. 2A and the supernatant (S) fractions were subjected to immunoprecipitations with rabbit anti-Bag6 antibody (αBag6) or rabbit control IgG antibody. Inputs and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as positive control for Bag6 binding. Arrow in A and B indicates full-length MAVS. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. (C) Mean±s.e.m. of MAVS levels that co-immunoprecipitate with Bag6 in control KO and SGTA KO cells for three independent experiments as in B. * P <0.05 (unpaired two-tailed t -test).

Article Snippet: Other antibodies used were as follows: anti-ATP13A1 (Proteintech 16244-1-AP, Lot 00007441; 1:2500 for IB), anti-Bag6 (Abnova H00007917-B01P, Lot J9271; 1:5000 for IB), anti-calnexin (Cell Signaling Technology #2679, Lot 4; 1:1000 for IB), anti-EMC1 (Abgent AP10226b, Lot SA100702BL; 1:500 for IB), anti-EMC2 (Santa Cruz Biotechnology sc-166011; 1:500 for IB), anti-EMC5 (Bethyl Laboratories A305-832A-M; 1:1000 for IB), anti-HA [Covance MMS-101R, Lot 14811501; 1:1000 for IB; 1:500 for immunofluorescence (IF)], anti-His (Sigma H1029, Lot 106M4768V; 1:3000 for IB), anti-Hsp70 (Abcam ab47455, Lot GR166016-49; 1:5000 for IB), anti-Hsp90 (Enzo Life Sciences ADI-SPA-846, Lot 07061528; 1:2000 for IB), anti-IRF3 (Cell Signaling Technology #11904, Lot 6; 1:1000 for IB), anti-phospho-IRF3 (Cell Signaling Technology #4947, Lot 13; 1:1000 for IB), anti-MAVS (Santa Cruz Biotechnology sc-166583, Lot L3119 and Lot C0421; 1:1000 for IB), anti-MAVS (Enzo Life Sciences ALX-210-929-C100, Lot 08061948; 1:100 for IP), anti-Myc (Merck Millipore 05-724, Lot 3095953; 1:5000 for IB), anti-Myc (Cell Signaling Technology #2276, Lot 24; 1:2000 for IF), anti-OMP25 (Proteintech 15666-1-AP, Lot 00068490; 1:1000 for IB), anti-OST48 [previously described ( ); 1:1000 for IB], anti-SGTA (Santa Cruz Biotechnology sc-130557, Lot E0809; 1:500 for IB), anti-Stx-5 (Synaptic Systems 110053, Lot 1-18 and Lot 110053/15; 1:5000 for IB, 1:100 for IP), anti-Stx-5 (Santa Cruz Biotechnology sc-365124, Lot H1419; 1:500 for IB), anti-TOM20 (Santa Cruz Biotechnology sc-17764, Lot H0320; 1:500 for IB), anti-TRC35 (Bethyl Laboratories A302-613A, Lot 1; 1:1000 for IB), anti-tubulin (gift from Keith Gull, University of Oxford, UK; 1:1000 for IB), anti-ubiquilin (Invitrogen 37-7700, Lot RJ241978; 1:1000 for IB), anti-ubiquilin-2 (Abcam ab217056, Lot GR3185004-6; 1:2000 for IB, 1:100 for IP), anti-rabbit IgG (Santa Cruz Biotechnology sc-2027, Lot F2413; 1:40 for IP) and anti-chicken IgY (Santa Cruz Biotechnology sc-2718, Lot L1412; 1:40 for IP).

Techniques: Control, Binding Assay, Western Blot, Positive Control, Derivative Assay, Two Tailed Test

ATP13A1 depletion has no visible effect on Bag6-MAVS interaction. (A) Proposed model. Bag6 recruits MAVS after its ATP13A1-mediated extraction from the ER membrane. Depleting ATP13A1 will decrease Bag6-MAVS interaction, as MAVS cannot be dislocated from the ER membrane. (B) ATP13A1 depletion does not grossly alter the levels of MAVS in the crude cytosolic supernatant fraction. (i) Control KO cells transfected with non-targeting (nt) or ATP13A1-targeting siRNAs (siATP13A1) were fractionated as shown in <xref ref-type=Fig. 2A . Equivalent amounts of supernatant (S) and pellet (P) fractions were analysed by immunoblotting for the indicated endogenous proteins. (ii) ATP13A1 and MAVS levels in siATP13A1-treated cells relative to nt siRNA-treated cells, where protein levels were set to 1. Shown are means±s.e.m. for five biological replicates as shown in Bi. **** P <0.0001; ns, not significant (two-tailed one-sample t -test). (iii) Mean±s.e.m. of the supernatant/total ratio of MAVS levels in siATP13A1-treated cells relative to the respective ratio in nt siRNA-treated cells for five independent experiments as in Bi. Same colour data points correspond to a single biological replicate; ns, not significant (paired two-tailed t -test). (C) ATP13A1 depletion does not affect Bag6-MAVS interaction. Supernatant (S) fractions from Bi were subjected to immunoprecipitations with rabbit anti-Bag6 antibody (αBag6) or rabbit control IgG antibody. Inputs and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as loading control as well as an internal control for equal Bag6 co-immunoprecipitation potential. Arrow in Bi and C indicates full-length MAVS. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. (D) Mean±s.e.m. of MAVS levels that co-immunoprecipitate with Bag6 in siATP13A1-treated cells relative to nt siRNA-treated cells for four independent experiments as shown in C. ns, not significant (paired two-tailed t -test). " width="100%" height="100%">

Journal: Journal of Cell Science

Article Title: Mitochondrial antiviral-signalling protein is a client of the BAG6 protein quality control complex

doi: 10.1242/jcs.259596

Figure Lengend Snippet: ATP13A1 depletion has no visible effect on Bag6-MAVS interaction. (A) Proposed model. Bag6 recruits MAVS after its ATP13A1-mediated extraction from the ER membrane. Depleting ATP13A1 will decrease Bag6-MAVS interaction, as MAVS cannot be dislocated from the ER membrane. (B) ATP13A1 depletion does not grossly alter the levels of MAVS in the crude cytosolic supernatant fraction. (i) Control KO cells transfected with non-targeting (nt) or ATP13A1-targeting siRNAs (siATP13A1) were fractionated as shown in Fig. 2A . Equivalent amounts of supernatant (S) and pellet (P) fractions were analysed by immunoblotting for the indicated endogenous proteins. (ii) ATP13A1 and MAVS levels in siATP13A1-treated cells relative to nt siRNA-treated cells, where protein levels were set to 1. Shown are means±s.e.m. for five biological replicates as shown in Bi. **** P <0.0001; ns, not significant (two-tailed one-sample t -test). (iii) Mean±s.e.m. of the supernatant/total ratio of MAVS levels in siATP13A1-treated cells relative to the respective ratio in nt siRNA-treated cells for five independent experiments as in Bi. Same colour data points correspond to a single biological replicate; ns, not significant (paired two-tailed t -test). (C) ATP13A1 depletion does not affect Bag6-MAVS interaction. Supernatant (S) fractions from Bi were subjected to immunoprecipitations with rabbit anti-Bag6 antibody (αBag6) or rabbit control IgG antibody. Inputs and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as loading control as well as an internal control for equal Bag6 co-immunoprecipitation potential. Arrow in Bi and C indicates full-length MAVS. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. (D) Mean±s.e.m. of MAVS levels that co-immunoprecipitate with Bag6 in siATP13A1-treated cells relative to nt siRNA-treated cells for four independent experiments as shown in C. ns, not significant (paired two-tailed t -test).

Article Snippet: Other antibodies used were as follows: anti-ATP13A1 (Proteintech 16244-1-AP, Lot 00007441; 1:2500 for IB), anti-Bag6 (Abnova H00007917-B01P, Lot J9271; 1:5000 for IB), anti-calnexin (Cell Signaling Technology #2679, Lot 4; 1:1000 for IB), anti-EMC1 (Abgent AP10226b, Lot SA100702BL; 1:500 for IB), anti-EMC2 (Santa Cruz Biotechnology sc-166011; 1:500 for IB), anti-EMC5 (Bethyl Laboratories A305-832A-M; 1:1000 for IB), anti-HA [Covance MMS-101R, Lot 14811501; 1:1000 for IB; 1:500 for immunofluorescence (IF)], anti-His (Sigma H1029, Lot 106M4768V; 1:3000 for IB), anti-Hsp70 (Abcam ab47455, Lot GR166016-49; 1:5000 for IB), anti-Hsp90 (Enzo Life Sciences ADI-SPA-846, Lot 07061528; 1:2000 for IB), anti-IRF3 (Cell Signaling Technology #11904, Lot 6; 1:1000 for IB), anti-phospho-IRF3 (Cell Signaling Technology #4947, Lot 13; 1:1000 for IB), anti-MAVS (Santa Cruz Biotechnology sc-166583, Lot L3119 and Lot C0421; 1:1000 for IB), anti-MAVS (Enzo Life Sciences ALX-210-929-C100, Lot 08061948; 1:100 for IP), anti-Myc (Merck Millipore 05-724, Lot 3095953; 1:5000 for IB), anti-Myc (Cell Signaling Technology #2276, Lot 24; 1:2000 for IF), anti-OMP25 (Proteintech 15666-1-AP, Lot 00068490; 1:1000 for IB), anti-OST48 [previously described ( ); 1:1000 for IB], anti-SGTA (Santa Cruz Biotechnology sc-130557, Lot E0809; 1:500 for IB), anti-Stx-5 (Synaptic Systems 110053, Lot 1-18 and Lot 110053/15; 1:5000 for IB, 1:100 for IP), anti-Stx-5 (Santa Cruz Biotechnology sc-365124, Lot H1419; 1:500 for IB), anti-TOM20 (Santa Cruz Biotechnology sc-17764, Lot H0320; 1:500 for IB), anti-TRC35 (Bethyl Laboratories A302-613A, Lot 1; 1:1000 for IB), anti-tubulin (gift from Keith Gull, University of Oxford, UK; 1:1000 for IB), anti-ubiquilin (Invitrogen 37-7700, Lot RJ241978; 1:1000 for IB), anti-ubiquilin-2 (Abcam ab217056, Lot GR3185004-6; 1:2000 for IB, 1:100 for IP), anti-rabbit IgG (Santa Cruz Biotechnology sc-2027, Lot F2413; 1:40 for IP) and anti-chicken IgY (Santa Cruz Biotechnology sc-2718, Lot L1412; 1:40 for IP).

Techniques: Extraction, Membrane, Control, Transfection, Western Blot, Two Tailed Test, Immunoprecipitation, Derivative Assay

EMC5 depletion enhances Bag6–MAVS interaction. (A) Proposed model. Bag6 binds MAVS before its EMC-mediated integration at the ER membrane. EMC deficiency will promote Bag6 binding to the cytosolic pool of MAVS that fails to be imported into the ER membrane. (B) EMC5 depletion does not grossly alter the levels of MAVS in the crude cytosolic supernatant fraction. (i,ii) Control KO cells transfected with non-targeting (nt) or EMC5-targeting siRNAs (siEMC5) were fractionated as shown in <xref ref-type=Fig. 2A . Equivalent amounts of supernatant (S) and pellet (P) fractions were analysed by immunoblotting for the indicated endogenous proteins. Blots resulting from the same membrane are clustered together. Tubulin and OST48 serve as loading controls for the supernatant and pellet fractions, respectively. (iii) EMC subunit and MAVS levels in siEMC5-treated cells relative to nt siRNA-treated cells, where protein levels were set to 1. Shown are means±s.e.m. for three-five biological replicates as shown in Bi,ii. **** P <0.0001; ** P <0.01; ns, not significant (one-way ANOVA with Tukey's multiple comparison tests). (iv) Mean±s.e.m. of the supernatant/total ratio of MAVS levels in siEMC5-treated cells relative to the respective ratio in nt siRNA-treated cells for five independent experiments as in Bii. Same colour data points correspond to a single biological replicate; ns, not significant (paired two-tailed t -test). (C) EMC5 depletion enhances Bag6-MAVS interaction. Supernatant (S) fractions from Bi,ii were subjected to immunoprecipitations with rabbit anti-Bag6 antibody (αBag6) or rabbit control IgG antibody. Inputs and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as loading control as well as an internal control for equal Bag6 co-immunoprecipitation potential. In Bi, the EMC2 and EMC1 bands are indicated by arrows. Arrow in Bii and C indicates full-length MAVS. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. (D) Mean±s.e.m. of MAVS levels that co-immunoprecipitate with Bag6 in siEMC5-treated cells relative to nt siRNA-treated cells for four independent experiments as shown in C. * P <0.05 (paired two-tailed t -test). " width="100%" height="100%">

Journal: Journal of Cell Science

Article Title: Mitochondrial antiviral-signalling protein is a client of the BAG6 protein quality control complex

doi: 10.1242/jcs.259596

Figure Lengend Snippet: EMC5 depletion enhances Bag6–MAVS interaction. (A) Proposed model. Bag6 binds MAVS before its EMC-mediated integration at the ER membrane. EMC deficiency will promote Bag6 binding to the cytosolic pool of MAVS that fails to be imported into the ER membrane. (B) EMC5 depletion does not grossly alter the levels of MAVS in the crude cytosolic supernatant fraction. (i,ii) Control KO cells transfected with non-targeting (nt) or EMC5-targeting siRNAs (siEMC5) were fractionated as shown in Fig. 2A . Equivalent amounts of supernatant (S) and pellet (P) fractions were analysed by immunoblotting for the indicated endogenous proteins. Blots resulting from the same membrane are clustered together. Tubulin and OST48 serve as loading controls for the supernatant and pellet fractions, respectively. (iii) EMC subunit and MAVS levels in siEMC5-treated cells relative to nt siRNA-treated cells, where protein levels were set to 1. Shown are means±s.e.m. for three-five biological replicates as shown in Bi,ii. **** P <0.0001; ** P <0.01; ns, not significant (one-way ANOVA with Tukey's multiple comparison tests). (iv) Mean±s.e.m. of the supernatant/total ratio of MAVS levels in siEMC5-treated cells relative to the respective ratio in nt siRNA-treated cells for five independent experiments as in Bii. Same colour data points correspond to a single biological replicate; ns, not significant (paired two-tailed t -test). (C) EMC5 depletion enhances Bag6-MAVS interaction. Supernatant (S) fractions from Bi,ii were subjected to immunoprecipitations with rabbit anti-Bag6 antibody (αBag6) or rabbit control IgG antibody. Inputs and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as loading control as well as an internal control for equal Bag6 co-immunoprecipitation potential. In Bi, the EMC2 and EMC1 bands are indicated by arrows. Arrow in Bii and C indicates full-length MAVS. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. (D) Mean±s.e.m. of MAVS levels that co-immunoprecipitate with Bag6 in siEMC5-treated cells relative to nt siRNA-treated cells for four independent experiments as shown in C. * P <0.05 (paired two-tailed t -test).

Article Snippet: Other antibodies used were as follows: anti-ATP13A1 (Proteintech 16244-1-AP, Lot 00007441; 1:2500 for IB), anti-Bag6 (Abnova H00007917-B01P, Lot J9271; 1:5000 for IB), anti-calnexin (Cell Signaling Technology #2679, Lot 4; 1:1000 for IB), anti-EMC1 (Abgent AP10226b, Lot SA100702BL; 1:500 for IB), anti-EMC2 (Santa Cruz Biotechnology sc-166011; 1:500 for IB), anti-EMC5 (Bethyl Laboratories A305-832A-M; 1:1000 for IB), anti-HA [Covance MMS-101R, Lot 14811501; 1:1000 for IB; 1:500 for immunofluorescence (IF)], anti-His (Sigma H1029, Lot 106M4768V; 1:3000 for IB), anti-Hsp70 (Abcam ab47455, Lot GR166016-49; 1:5000 for IB), anti-Hsp90 (Enzo Life Sciences ADI-SPA-846, Lot 07061528; 1:2000 for IB), anti-IRF3 (Cell Signaling Technology #11904, Lot 6; 1:1000 for IB), anti-phospho-IRF3 (Cell Signaling Technology #4947, Lot 13; 1:1000 for IB), anti-MAVS (Santa Cruz Biotechnology sc-166583, Lot L3119 and Lot C0421; 1:1000 for IB), anti-MAVS (Enzo Life Sciences ALX-210-929-C100, Lot 08061948; 1:100 for IP), anti-Myc (Merck Millipore 05-724, Lot 3095953; 1:5000 for IB), anti-Myc (Cell Signaling Technology #2276, Lot 24; 1:2000 for IF), anti-OMP25 (Proteintech 15666-1-AP, Lot 00068490; 1:1000 for IB), anti-OST48 [previously described ( ); 1:1000 for IB], anti-SGTA (Santa Cruz Biotechnology sc-130557, Lot E0809; 1:500 for IB), anti-Stx-5 (Synaptic Systems 110053, Lot 1-18 and Lot 110053/15; 1:5000 for IB, 1:100 for IP), anti-Stx-5 (Santa Cruz Biotechnology sc-365124, Lot H1419; 1:500 for IB), anti-TOM20 (Santa Cruz Biotechnology sc-17764, Lot H0320; 1:500 for IB), anti-TRC35 (Bethyl Laboratories A302-613A, Lot 1; 1:1000 for IB), anti-tubulin (gift from Keith Gull, University of Oxford, UK; 1:1000 for IB), anti-ubiquilin (Invitrogen 37-7700, Lot RJ241978; 1:1000 for IB), anti-ubiquilin-2 (Abcam ab217056, Lot GR3185004-6; 1:2000 for IB, 1:100 for IP), anti-rabbit IgG (Santa Cruz Biotechnology sc-2027, Lot F2413; 1:40 for IP) and anti-chicken IgY (Santa Cruz Biotechnology sc-2718, Lot L1412; 1:40 for IP).

Techniques: Membrane, Binding Assay, Control, Transfection, Western Blot, Comparison, Two Tailed Test, Immunoprecipitation, Derivative Assay

Stimulation with poly(I:C) compromises the Bag6–MAVS interaction. (A) Kinetics of IRF3 activation in response to cytosolic poly(I:C). Control KO cells were mock-transfected ( t =0) or transfected with poly(I:C) for various times before immunoblotting for the indicated proteins. Activation of endogenous IRF3 was assessed by induction of its phosphorylation and dimerisation. Phosphorylated IRF3 blot is representative of six independent experiments. Western blot for the detection of IRF3 dimer is representative of two independent experiments. pIRF3, phosphorylated IRF3; (IRF3)2, IRF3 dimer. (B) Stimulation with cytosolic poly(I:C) does not grossly alter the levels of MAVS in the crude cytosolic supernatant fraction. (i) Control KO cells were mock-transfected ( t =0) or transfected with poly(I:C) for various times before their fractionation as shown in <xref ref-type=Fig. 2A . The resulting supernatant (S) and pellet (P) fractions were analysed by immunoblotting for the indicated endogenous proteins. (ii,iii) Mean±s.e.m. of the (ii) pellet/total ratio and (iii) supernatant/total ratio of MAVS levels in poly(I:C)-transfected cells relative to the respective ratios in mock-transfected cells ( t =0) for six independent experiments as in Bi. ** P <0.01; ns, not significant (ordinary one-way ANOVA with Dunnett's multiple comparison tests). (C) Cytosolic poly(I:C) impairs Bag6–MAVS interaction. Supernatant fractions from Bi were subjected to immunoprecipitations with rabbit anti-Bag6 antibody (αBag6) or rabbit control IgG antibody. Inputs and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as loading control as well as internal control for comparable Bag6 binding. Arrow in MAVS blot in Bi and C indicates full-length MAVS. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. (D) Mean±s.e.m. of MAVS levels that co-immunoprecipitate with Bag6 in poly(I:C)-transfected relative to mock-transfected cells ( t =0) for six independent experiments as shown in C. * P <0.05; ns, not significant (one-way ANOVA with Dunnett's multiple comparison tests). " width="100%" height="100%">

Journal: Journal of Cell Science

Article Title: Mitochondrial antiviral-signalling protein is a client of the BAG6 protein quality control complex

doi: 10.1242/jcs.259596

Figure Lengend Snippet: Stimulation with poly(I:C) compromises the Bag6–MAVS interaction. (A) Kinetics of IRF3 activation in response to cytosolic poly(I:C). Control KO cells were mock-transfected ( t =0) or transfected with poly(I:C) for various times before immunoblotting for the indicated proteins. Activation of endogenous IRF3 was assessed by induction of its phosphorylation and dimerisation. Phosphorylated IRF3 blot is representative of six independent experiments. Western blot for the detection of IRF3 dimer is representative of two independent experiments. pIRF3, phosphorylated IRF3; (IRF3)2, IRF3 dimer. (B) Stimulation with cytosolic poly(I:C) does not grossly alter the levels of MAVS in the crude cytosolic supernatant fraction. (i) Control KO cells were mock-transfected ( t =0) or transfected with poly(I:C) for various times before their fractionation as shown in Fig. 2A . The resulting supernatant (S) and pellet (P) fractions were analysed by immunoblotting for the indicated endogenous proteins. (ii,iii) Mean±s.e.m. of the (ii) pellet/total ratio and (iii) supernatant/total ratio of MAVS levels in poly(I:C)-transfected cells relative to the respective ratios in mock-transfected cells ( t =0) for six independent experiments as in Bi. ** P <0.01; ns, not significant (ordinary one-way ANOVA with Dunnett's multiple comparison tests). (C) Cytosolic poly(I:C) impairs Bag6–MAVS interaction. Supernatant fractions from Bi were subjected to immunoprecipitations with rabbit anti-Bag6 antibody (αBag6) or rabbit control IgG antibody. Inputs and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as loading control as well as internal control for comparable Bag6 binding. Arrow in MAVS blot in Bi and C indicates full-length MAVS. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. (D) Mean±s.e.m. of MAVS levels that co-immunoprecipitate with Bag6 in poly(I:C)-transfected relative to mock-transfected cells ( t =0) for six independent experiments as shown in C. * P <0.05; ns, not significant (one-way ANOVA with Dunnett's multiple comparison tests).

Article Snippet: Other antibodies used were as follows: anti-ATP13A1 (Proteintech 16244-1-AP, Lot 00007441; 1:2500 for IB), anti-Bag6 (Abnova H00007917-B01P, Lot J9271; 1:5000 for IB), anti-calnexin (Cell Signaling Technology #2679, Lot 4; 1:1000 for IB), anti-EMC1 (Abgent AP10226b, Lot SA100702BL; 1:500 for IB), anti-EMC2 (Santa Cruz Biotechnology sc-166011; 1:500 for IB), anti-EMC5 (Bethyl Laboratories A305-832A-M; 1:1000 for IB), anti-HA [Covance MMS-101R, Lot 14811501; 1:1000 for IB; 1:500 for immunofluorescence (IF)], anti-His (Sigma H1029, Lot 106M4768V; 1:3000 for IB), anti-Hsp70 (Abcam ab47455, Lot GR166016-49; 1:5000 for IB), anti-Hsp90 (Enzo Life Sciences ADI-SPA-846, Lot 07061528; 1:2000 for IB), anti-IRF3 (Cell Signaling Technology #11904, Lot 6; 1:1000 for IB), anti-phospho-IRF3 (Cell Signaling Technology #4947, Lot 13; 1:1000 for IB), anti-MAVS (Santa Cruz Biotechnology sc-166583, Lot L3119 and Lot C0421; 1:1000 for IB), anti-MAVS (Enzo Life Sciences ALX-210-929-C100, Lot 08061948; 1:100 for IP), anti-Myc (Merck Millipore 05-724, Lot 3095953; 1:5000 for IB), anti-Myc (Cell Signaling Technology #2276, Lot 24; 1:2000 for IF), anti-OMP25 (Proteintech 15666-1-AP, Lot 00068490; 1:1000 for IB), anti-OST48 [previously described ( ); 1:1000 for IB], anti-SGTA (Santa Cruz Biotechnology sc-130557, Lot E0809; 1:500 for IB), anti-Stx-5 (Synaptic Systems 110053, Lot 1-18 and Lot 110053/15; 1:5000 for IB, 1:100 for IP), anti-Stx-5 (Santa Cruz Biotechnology sc-365124, Lot H1419; 1:500 for IB), anti-TOM20 (Santa Cruz Biotechnology sc-17764, Lot H0320; 1:500 for IB), anti-TRC35 (Bethyl Laboratories A302-613A, Lot 1; 1:1000 for IB), anti-tubulin (gift from Keith Gull, University of Oxford, UK; 1:1000 for IB), anti-ubiquilin (Invitrogen 37-7700, Lot RJ241978; 1:1000 for IB), anti-ubiquilin-2 (Abcam ab217056, Lot GR3185004-6; 1:2000 for IB, 1:100 for IP), anti-rabbit IgG (Santa Cruz Biotechnology sc-2027, Lot F2413; 1:40 for IP) and anti-chicken IgY (Santa Cruz Biotechnology sc-2718, Lot L1412; 1:40 for IP).

Techniques: Activation Assay, Control, Transfection, Western Blot, Fractionation, Comparison, Binding Assay, Derivative Assay

Working model for the role of the BAG6 complex during MAVS biogenesis. The molecular basis for the post-translational targeting and insertion of TA proteins such as MAVS into the mitochondrial outer membrane (MOM) are poorly defined (pathway 1a). Failed mitochondrial import can result in the mislocalisation of MAVS to the cytosol, where it may be recognised by one or more quality control machineries and targeted for proteasomal degradation (pathway 1b). A fraction of newly synthesised MAVS also engages the BAG6 complex either directly (pathway 3) or after transfer from SGTA (pathway 2). In the later case, SGTA may bind MAVS as its TMD leaves the ribosomal exit tunnel or after its release into the cytosol . The BAG6 complex acts upstream of MAVS ‘misinsertion’ into the ER membrane, which is most likely facilitated by the EMC (pathway 4a). It is currently unknown whether additional factors act between the BAG6 complex and the EMC insertase (pathway 4a, see ?). BAG6 binding might also enable the proteasomal degradation of mislocalised MAVS (pathway 4b). At the ER membrane, ‘mistargeted’ MAVS can be recognised by the P5A-ATPase ATP13A1 and extracted to the cytosol (pathway 5a) for either proteasomal degradation (pathway 5b) or reinsertion into the MOM via an ER-SURF pathway (pathway 5c). The access of an ER-localised pool of MAVS to ER-MOM contacts sites (MAMs) that facilitate MAVS oligomerisation and downstream signalling (pathway 6) may be modulated by the innate immune response.

Journal: Journal of Cell Science

Article Title: Mitochondrial antiviral-signalling protein is a client of the BAG6 protein quality control complex

doi: 10.1242/jcs.259596

Figure Lengend Snippet: Working model for the role of the BAG6 complex during MAVS biogenesis. The molecular basis for the post-translational targeting and insertion of TA proteins such as MAVS into the mitochondrial outer membrane (MOM) are poorly defined (pathway 1a). Failed mitochondrial import can result in the mislocalisation of MAVS to the cytosol, where it may be recognised by one or more quality control machineries and targeted for proteasomal degradation (pathway 1b). A fraction of newly synthesised MAVS also engages the BAG6 complex either directly (pathway 3) or after transfer from SGTA (pathway 2). In the later case, SGTA may bind MAVS as its TMD leaves the ribosomal exit tunnel or after its release into the cytosol . The BAG6 complex acts upstream of MAVS ‘misinsertion’ into the ER membrane, which is most likely facilitated by the EMC (pathway 4a). It is currently unknown whether additional factors act between the BAG6 complex and the EMC insertase (pathway 4a, see ?). BAG6 binding might also enable the proteasomal degradation of mislocalised MAVS (pathway 4b). At the ER membrane, ‘mistargeted’ MAVS can be recognised by the P5A-ATPase ATP13A1 and extracted to the cytosol (pathway 5a) for either proteasomal degradation (pathway 5b) or reinsertion into the MOM via an ER-SURF pathway (pathway 5c). The access of an ER-localised pool of MAVS to ER-MOM contacts sites (MAMs) that facilitate MAVS oligomerisation and downstream signalling (pathway 6) may be modulated by the innate immune response.

Article Snippet: Other antibodies used were as follows: anti-ATP13A1 (Proteintech 16244-1-AP, Lot 00007441; 1:2500 for IB), anti-Bag6 (Abnova H00007917-B01P, Lot J9271; 1:5000 for IB), anti-calnexin (Cell Signaling Technology #2679, Lot 4; 1:1000 for IB), anti-EMC1 (Abgent AP10226b, Lot SA100702BL; 1:500 for IB), anti-EMC2 (Santa Cruz Biotechnology sc-166011; 1:500 for IB), anti-EMC5 (Bethyl Laboratories A305-832A-M; 1:1000 for IB), anti-HA [Covance MMS-101R, Lot 14811501; 1:1000 for IB; 1:500 for immunofluorescence (IF)], anti-His (Sigma H1029, Lot 106M4768V; 1:3000 for IB), anti-Hsp70 (Abcam ab47455, Lot GR166016-49; 1:5000 for IB), anti-Hsp90 (Enzo Life Sciences ADI-SPA-846, Lot 07061528; 1:2000 for IB), anti-IRF3 (Cell Signaling Technology #11904, Lot 6; 1:1000 for IB), anti-phospho-IRF3 (Cell Signaling Technology #4947, Lot 13; 1:1000 for IB), anti-MAVS (Santa Cruz Biotechnology sc-166583, Lot L3119 and Lot C0421; 1:1000 for IB), anti-MAVS (Enzo Life Sciences ALX-210-929-C100, Lot 08061948; 1:100 for IP), anti-Myc (Merck Millipore 05-724, Lot 3095953; 1:5000 for IB), anti-Myc (Cell Signaling Technology #2276, Lot 24; 1:2000 for IF), anti-OMP25 (Proteintech 15666-1-AP, Lot 00068490; 1:1000 for IB), anti-OST48 [previously described ( ); 1:1000 for IB], anti-SGTA (Santa Cruz Biotechnology sc-130557, Lot E0809; 1:500 for IB), anti-Stx-5 (Synaptic Systems 110053, Lot 1-18 and Lot 110053/15; 1:5000 for IB, 1:100 for IP), anti-Stx-5 (Santa Cruz Biotechnology sc-365124, Lot H1419; 1:500 for IB), anti-TOM20 (Santa Cruz Biotechnology sc-17764, Lot H0320; 1:500 for IB), anti-TRC35 (Bethyl Laboratories A302-613A, Lot 1; 1:1000 for IB), anti-tubulin (gift from Keith Gull, University of Oxford, UK; 1:1000 for IB), anti-ubiquilin (Invitrogen 37-7700, Lot RJ241978; 1:1000 for IB), anti-ubiquilin-2 (Abcam ab217056, Lot GR3185004-6; 1:2000 for IB, 1:100 for IP), anti-rabbit IgG (Santa Cruz Biotechnology sc-2027, Lot F2413; 1:40 for IP) and anti-chicken IgY (Santa Cruz Biotechnology sc-2718, Lot L1412; 1:40 for IP).

Techniques: Membrane, Control, Binding Assay

DERL2 interacting with BAG6. A Schematic flow chart of the experimental design. B 293T cells were transfected with the Flag-DERL2 or/and HA-BAG6 vectors. Forty-eight hours later, the immunoprecipitated complex with Anti-HA beads was analyzed using the corresponding antibodies. C 293T cells were transfected with the Flag- DERL2 or/and HA- BAG6 vectors. Forty-eight hours later, the immunoprecipitated complex with anti-Flag beads was analyzed using the corresponding antibodies. D Fluorescence confocal microscopy analysis of the colocalization of DERL2 with BAG6 in the QBC939 cells transfected with. Flag- DERL2 or/and HA- BAG6 vectors. E Western blot analysis of BAG6 expression in the QBC939 cells upon DERL2 depletion or not. Significance: *** p < 0.001. F Western blot analysis of BAG6 expression in the QBC939 cells transfected the increased dose of Flag- DERL2 vectors. G Western blot analysis of BAG6 expression in the BAG6-overexpressing QBC939 cells transfected with Flag- DERL2 vectors or not. Forty-eight hours later, Chx was added. At different times later, Flag/HA antibodies were used to detect the DERL2 or BAG6 expression

Journal: Journal of Physiology and Biochemistry

Article Title: DERL2 (derlin 2) stabilizes BAG6 (BAG cochaperone 6) in chemotherapy resistance of cholangiocarcinoma

doi: 10.1007/s13105-023-00986-w

Figure Lengend Snippet: DERL2 interacting with BAG6. A Schematic flow chart of the experimental design. B 293T cells were transfected with the Flag-DERL2 or/and HA-BAG6 vectors. Forty-eight hours later, the immunoprecipitated complex with Anti-HA beads was analyzed using the corresponding antibodies. C 293T cells were transfected with the Flag- DERL2 or/and HA- BAG6 vectors. Forty-eight hours later, the immunoprecipitated complex with anti-Flag beads was analyzed using the corresponding antibodies. D Fluorescence confocal microscopy analysis of the colocalization of DERL2 with BAG6 in the QBC939 cells transfected with. Flag- DERL2 or/and HA- BAG6 vectors. E Western blot analysis of BAG6 expression in the QBC939 cells upon DERL2 depletion or not. Significance: *** p < 0.001. F Western blot analysis of BAG6 expression in the QBC939 cells transfected the increased dose of Flag- DERL2 vectors. G Western blot analysis of BAG6 expression in the BAG6-overexpressing QBC939 cells transfected with Flag- DERL2 vectors or not. Forty-eight hours later, Chx was added. At different times later, Flag/HA antibodies were used to detect the DERL2 or BAG6 expression

Article Snippet: Anti-Flag antibody (Cat#BN20611, Biorigin, China), Anti-HA antibody (Cat#DE0612, Biorigin, China), Anti-GAPDH antibody (Cat#DE0621, Biorigin, China), anti-DERL2 antibody (Cat# NDC-ASJ-CJRQXJ-50, Amylet scientific, China), anti-BAG6 antibody (Cat#K112847P, Solarbio, China), Anti-PARP1 antibody (Cat#ab191217, Abcam, USA), Anti-Cleaved PARP1 antibody (Cat#ab32064, Abcam, USA), Anti-Capase-3 antibody (Cat#ab32351, Abcam, USA), Anti-Cleaved Capase-3 antibody (Cat#E83-77, Abcam, USA), Anti-GAPDH antibody (Cat#ab9485, USA), and Anti-beta Actin antibody (Cat#ab8227, USA) were used in western blot analysis.

Techniques: Transfection, Immunoprecipitation, Fluorescence, Confocal Microscopy, Western Blot, Expressing

GEPIA analysis of the correlation of DERL2 with BAG6 in CHOL. A GEPIA analysis of the correlation of DERL2 (TPM) and BAG6 in CHOL. B GEPIA analysis of the correlation of DERL2 (FPKM) and BAG6 in CHOL

Journal: Journal of Physiology and Biochemistry

Article Title: DERL2 (derlin 2) stabilizes BAG6 (BAG cochaperone 6) in chemotherapy resistance of cholangiocarcinoma

doi: 10.1007/s13105-023-00986-w

Figure Lengend Snippet: GEPIA analysis of the correlation of DERL2 with BAG6 in CHOL. A GEPIA analysis of the correlation of DERL2 (TPM) and BAG6 in CHOL. B GEPIA analysis of the correlation of DERL2 (FPKM) and BAG6 in CHOL

Article Snippet: Anti-Flag antibody (Cat#BN20611, Biorigin, China), Anti-HA antibody (Cat#DE0612, Biorigin, China), Anti-GAPDH antibody (Cat#DE0621, Biorigin, China), anti-DERL2 antibody (Cat# NDC-ASJ-CJRQXJ-50, Amylet scientific, China), anti-BAG6 antibody (Cat#K112847P, Solarbio, China), Anti-PARP1 antibody (Cat#ab191217, Abcam, USA), Anti-Cleaved PARP1 antibody (Cat#ab32064, Abcam, USA), Anti-Capase-3 antibody (Cat#ab32351, Abcam, USA), Anti-Cleaved Capase-3 antibody (Cat#E83-77, Abcam, USA), Anti-GAPDH antibody (Cat#ab9485, USA), and Anti-beta Actin antibody (Cat#ab8227, USA) were used in western blot analysis.

Techniques:

MAVS is a high-confidence proximal interactor of SGTA. (A) Left, schematic of human SGTA–BioID2–HA displaying its protein–protein interaction modules. UBLbd, N-terminal domain that binds to the ubiquitin-like (UBL) domains of Ubl4A and Bag6; TPRd, central tetratricopeptide repeat (TPR) domain that interacts with heat-shock proteins; substratebd (sub/tebd), C-terminal domain that contains the hydrophobic substrate-binding site. Right, schematics of the SGTA–BioID2 mutants and respective disrupted interactions. Mutated amino acids are indicated. (B) Scheme for the BioID2-mediated proximity labelling and identification of SGTA substrates and cofactors using SGTA KO cells (see Fig. S1 ) transiently expressing wild-type (wt) SGTA-BioID2 or mutant variants shown in A. Cells expressing Myc–BioID2 or PEX19–BioID2 serve as two independent controls to exclude non-specific interactors. (C) Heat map representing log2-transformed fold changes in the protein intensities of significant (BFDR<0.05) wild-type (wt)/mutant SGTA-specific preys relative to both the Myc–BioID2 and PEX19–BioID2 controls. Individual rounded values are depicted in the heat map. A non-significant prey is shown as a white box (three biological replicates; see Tables S1–S3 for list of all proteins detected). (D) Validation of selected SGTA-associated candidates from C by immunoblotting. SGTA KO cells expressing the indicated BioID2-tagged baits were treated with biotin for 8 h and lysed with RIPA buffer. The resulting extracts were subjected to affinity purification with streptavidin beads and the bound material eluted using a biotin-containing buffer. The input and eluted material were analysed by immunoblotting for the indicated endogenous proteins. Stx-5 can be observed as two bands (indicated by arrows) corresponding to two isoforms, a 42 kDa-ER and a 35 kDa-Golgi isoform that result from an alternative initiation of translation . Blots representative of three independent biological replicates.

Journal: Journal of Cell Science

Article Title: Mitochondrial antiviral-signalling protein is a client of the BAG6 protein quality control complex

doi: 10.1242/jcs.259596

Figure Lengend Snippet: MAVS is a high-confidence proximal interactor of SGTA. (A) Left, schematic of human SGTA–BioID2–HA displaying its protein–protein interaction modules. UBLbd, N-terminal domain that binds to the ubiquitin-like (UBL) domains of Ubl4A and Bag6; TPRd, central tetratricopeptide repeat (TPR) domain that interacts with heat-shock proteins; substratebd (sub/tebd), C-terminal domain that contains the hydrophobic substrate-binding site. Right, schematics of the SGTA–BioID2 mutants and respective disrupted interactions. Mutated amino acids are indicated. (B) Scheme for the BioID2-mediated proximity labelling and identification of SGTA substrates and cofactors using SGTA KO cells (see Fig. S1 ) transiently expressing wild-type (wt) SGTA-BioID2 or mutant variants shown in A. Cells expressing Myc–BioID2 or PEX19–BioID2 serve as two independent controls to exclude non-specific interactors. (C) Heat map representing log2-transformed fold changes in the protein intensities of significant (BFDR<0.05) wild-type (wt)/mutant SGTA-specific preys relative to both the Myc–BioID2 and PEX19–BioID2 controls. Individual rounded values are depicted in the heat map. A non-significant prey is shown as a white box (three biological replicates; see Tables S1–S3 for list of all proteins detected). (D) Validation of selected SGTA-associated candidates from C by immunoblotting. SGTA KO cells expressing the indicated BioID2-tagged baits were treated with biotin for 8 h and lysed with RIPA buffer. The resulting extracts were subjected to affinity purification with streptavidin beads and the bound material eluted using a biotin-containing buffer. The input and eluted material were analysed by immunoblotting for the indicated endogenous proteins. Stx-5 can be observed as two bands (indicated by arrows) corresponding to two isoforms, a 42 kDa-ER and a 35 kDa-Golgi isoform that result from an alternative initiation of translation . Blots representative of three independent biological replicates.

Article Snippet: Anti-Bag6 rabbit polyclonal antibodies [1:1000 for immunoblotting (IB); 1:100 for immunoprecipitation (IP)] were raised against a synthetic peptide corresponding to residues 112–130 of human Bag6 isoform 2 (GSPPGTRGPGASVHDRNAN; synthesised by Peptide Specialty Laboratories GmbH) and affinity purified (also described in ).

Techniques: Ubiquitin Proteomics, Binding Assay, Expressing, Mutagenesis, Transformation Assay, Biomarker Discovery, Western Blot, Affinity Purification

SGTA interacts with MAVS. (A) A cytosolic pool of endogenous MAVS can be observed at steady-state. Top, schematic of subcellular fractionation protocol used to separate the cell homogenate into crude cytosolic supernatant (S) and membrane-associated pellet (P) fractions. Bottom, detergent-free extracts from control KO cells (see Fig. S1 ) were fractionated as shown above. Equivalent amounts of each fraction were analysed by immunoblotting for MAVS and various compartmental markers. Bag6, SGTA and tubulin (cytosolic markers), TOM20 (mitochondrial outer membrane marker) and calnexin (CNX, ER membrane marker) serve as fractionation controls. Note that the MAVS-specific antibody, raised against amino acids 1–135 of human MAVS, detected the ∼80 kDa full-length MAVS (marked by an arrow) and multiple shorter variants that most likely represent C-terminally degraded products or processed forms of the full-length protein (see also ). Quantification of the levels of full-length MAVS recovered in the cytosolic fraction is indicated below the MAVS blot. Value represents mean±s.e.m. from three independent experiments. (B) MAVS co-immunoprecipitates with SGTA. The supernatant (S) fraction from A was subjected to immunoprecipitations with equal amounts of chicken anti-SGTA antibody (αSGTA) or chicken IgY antibody (control for non-specific binding). Input and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. Bag6 served as positive control for SGTA binding. In A and B, arrows next to the Stx-5 blots indicate the two Stx-5 isoforms. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. Blots representative of three independent experiments. (C) In vitro translated MAVS interacts with recombinant SGTA via its transmembrane domain (TMD). Top, schematic of FLAG–MAVS displaying its N-terminal caspase activation and recruitment domain (CARD) and C-terminal TMD. Bottom, FLAG-MAVS full-length, ΔCARD or ΔTMD truncated variants were translated in vitro in the absence or presence (+) of 2 µM His-S-tag-SGTA. A 10% sample of the total translation products was subjected to denaturing immunoprecipitations with anti-FLAG antibody (totals), while the rest was incubated with HisPur cobalt resin and bound proteins were eluted using imidazole (eluates). Totals and eluates were resolved by SDS-PAGE and results visualised by phosphorimaging. Downward arrows indicate full-length and ΔCARD FLAG–MAVS selectively bound by His-S-tag-SGTA. His-S-tag-SGTA and its binding partners within rabbit reticulocyte lysate were released from the resin by incubating the beads with SDS sample buffer (beads) and samples were analysed by immunoblotting (IB). The anti-His and anti-Bag6 immunoblots indicate uniform binding of Bag6 binding-competent His-S-tag-SGTA to beads. Results shown in C are representative of two independent experiments.

Journal: Journal of Cell Science

Article Title: Mitochondrial antiviral-signalling protein is a client of the BAG6 protein quality control complex

doi: 10.1242/jcs.259596

Figure Lengend Snippet: SGTA interacts with MAVS. (A) A cytosolic pool of endogenous MAVS can be observed at steady-state. Top, schematic of subcellular fractionation protocol used to separate the cell homogenate into crude cytosolic supernatant (S) and membrane-associated pellet (P) fractions. Bottom, detergent-free extracts from control KO cells (see Fig. S1 ) were fractionated as shown above. Equivalent amounts of each fraction were analysed by immunoblotting for MAVS and various compartmental markers. Bag6, SGTA and tubulin (cytosolic markers), TOM20 (mitochondrial outer membrane marker) and calnexin (CNX, ER membrane marker) serve as fractionation controls. Note that the MAVS-specific antibody, raised against amino acids 1–135 of human MAVS, detected the ∼80 kDa full-length MAVS (marked by an arrow) and multiple shorter variants that most likely represent C-terminally degraded products or processed forms of the full-length protein (see also ). Quantification of the levels of full-length MAVS recovered in the cytosolic fraction is indicated below the MAVS blot. Value represents mean±s.e.m. from three independent experiments. (B) MAVS co-immunoprecipitates with SGTA. The supernatant (S) fraction from A was subjected to immunoprecipitations with equal amounts of chicken anti-SGTA antibody (αSGTA) or chicken IgY antibody (control for non-specific binding). Input and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. Bag6 served as positive control for SGTA binding. In A and B, arrows next to the Stx-5 blots indicate the two Stx-5 isoforms. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. Blots representative of three independent experiments. (C) In vitro translated MAVS interacts with recombinant SGTA via its transmembrane domain (TMD). Top, schematic of FLAG–MAVS displaying its N-terminal caspase activation and recruitment domain (CARD) and C-terminal TMD. Bottom, FLAG-MAVS full-length, ΔCARD or ΔTMD truncated variants were translated in vitro in the absence or presence (+) of 2 µM His-S-tag-SGTA. A 10% sample of the total translation products was subjected to denaturing immunoprecipitations with anti-FLAG antibody (totals), while the rest was incubated with HisPur cobalt resin and bound proteins were eluted using imidazole (eluates). Totals and eluates were resolved by SDS-PAGE and results visualised by phosphorimaging. Downward arrows indicate full-length and ΔCARD FLAG–MAVS selectively bound by His-S-tag-SGTA. His-S-tag-SGTA and its binding partners within rabbit reticulocyte lysate were released from the resin by incubating the beads with SDS sample buffer (beads) and samples were analysed by immunoblotting (IB). The anti-His and anti-Bag6 immunoblots indicate uniform binding of Bag6 binding-competent His-S-tag-SGTA to beads. Results shown in C are representative of two independent experiments.

Article Snippet: Anti-Bag6 rabbit polyclonal antibodies [1:1000 for immunoblotting (IB); 1:100 for immunoprecipitation (IP)] were raised against a synthetic peptide corresponding to residues 112–130 of human Bag6 isoform 2 (GSPPGTRGPGASVHDRNAN; synthesised by Peptide Specialty Laboratories GmbH) and affinity purified (also described in ).

Techniques: Fractionation, Membrane, Control, Western Blot, Marker, Binding Assay, Positive Control, Derivative Assay, In Vitro, Recombinant, Activation Assay, Incubation, SDS Page

Bag6 interacts with MAVS. (A) MAVS co-immunoprecipitates with Bag6. Control KO cells were fractionated as shown in <xref ref-type=Fig. 2A and the supernatant (S) fraction was subjected to immunoprecipitations with equal amounts of rabbit anti-Bag6 antibody (αBag6) or rabbit IgG antibody (control for non-specific binding). Input and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as positive control for Bag6 binding. (B) SGTA facilitates Bag6–MAVS interaction. Control KO and SGTA KO cells were fractionated as shown in Fig. 2A and the supernatant (S) fractions were subjected to immunoprecipitations with rabbit anti-Bag6 antibody (αBag6) or rabbit control IgG antibody. Inputs and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as positive control for Bag6 binding. Arrow in A and B indicates full-length MAVS. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. (C) Mean±s.e.m. of MAVS levels that co-immunoprecipitate with Bag6 in control KO and SGTA KO cells for three independent experiments as in B. * P <0.05 (unpaired two-tailed t -test). " width="100%" height="100%">

Journal: Journal of Cell Science

Article Title: Mitochondrial antiviral-signalling protein is a client of the BAG6 protein quality control complex

doi: 10.1242/jcs.259596

Figure Lengend Snippet: Bag6 interacts with MAVS. (A) MAVS co-immunoprecipitates with Bag6. Control KO cells were fractionated as shown in Fig. 2A and the supernatant (S) fraction was subjected to immunoprecipitations with equal amounts of rabbit anti-Bag6 antibody (αBag6) or rabbit IgG antibody (control for non-specific binding). Input and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as positive control for Bag6 binding. (B) SGTA facilitates Bag6–MAVS interaction. Control KO and SGTA KO cells were fractionated as shown in Fig. 2A and the supernatant (S) fractions were subjected to immunoprecipitations with rabbit anti-Bag6 antibody (αBag6) or rabbit control IgG antibody. Inputs and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as positive control for Bag6 binding. Arrow in A and B indicates full-length MAVS. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. (C) Mean±s.e.m. of MAVS levels that co-immunoprecipitate with Bag6 in control KO and SGTA KO cells for three independent experiments as in B. * P <0.05 (unpaired two-tailed t -test).

Article Snippet: Anti-Bag6 rabbit polyclonal antibodies [1:1000 for immunoblotting (IB); 1:100 for immunoprecipitation (IP)] were raised against a synthetic peptide corresponding to residues 112–130 of human Bag6 isoform 2 (GSPPGTRGPGASVHDRNAN; synthesised by Peptide Specialty Laboratories GmbH) and affinity purified (also described in ).

Techniques: Control, Binding Assay, Western Blot, Positive Control, Derivative Assay, Two Tailed Test

ATP13A1 depletion has no visible effect on Bag6-MAVS interaction. (A) Proposed model. Bag6 recruits MAVS after its ATP13A1-mediated extraction from the ER membrane. Depleting ATP13A1 will decrease Bag6-MAVS interaction, as MAVS cannot be dislocated from the ER membrane. (B) ATP13A1 depletion does not grossly alter the levels of MAVS in the crude cytosolic supernatant fraction. (i) Control KO cells transfected with non-targeting (nt) or ATP13A1-targeting siRNAs (siATP13A1) were fractionated as shown in <xref ref-type=Fig. 2A . Equivalent amounts of supernatant (S) and pellet (P) fractions were analysed by immunoblotting for the indicated endogenous proteins. (ii) ATP13A1 and MAVS levels in siATP13A1-treated cells relative to nt siRNA-treated cells, where protein levels were set to 1. Shown are means±s.e.m. for five biological replicates as shown in Bi. **** P <0.0001; ns, not significant (two-tailed one-sample t -test). (iii) Mean±s.e.m. of the supernatant/total ratio of MAVS levels in siATP13A1-treated cells relative to the respective ratio in nt siRNA-treated cells for five independent experiments as in Bi. Same colour data points correspond to a single biological replicate; ns, not significant (paired two-tailed t -test). (C) ATP13A1 depletion does not affect Bag6-MAVS interaction. Supernatant (S) fractions from Bi were subjected to immunoprecipitations with rabbit anti-Bag6 antibody (αBag6) or rabbit control IgG antibody. Inputs and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as loading control as well as an internal control for equal Bag6 co-immunoprecipitation potential. Arrow in Bi and C indicates full-length MAVS. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. (D) Mean±s.e.m. of MAVS levels that co-immunoprecipitate with Bag6 in siATP13A1-treated cells relative to nt siRNA-treated cells for four independent experiments as shown in C. ns, not significant (paired two-tailed t -test). " width="100%" height="100%">

Journal: Journal of Cell Science

Article Title: Mitochondrial antiviral-signalling protein is a client of the BAG6 protein quality control complex

doi: 10.1242/jcs.259596

Figure Lengend Snippet: ATP13A1 depletion has no visible effect on Bag6-MAVS interaction. (A) Proposed model. Bag6 recruits MAVS after its ATP13A1-mediated extraction from the ER membrane. Depleting ATP13A1 will decrease Bag6-MAVS interaction, as MAVS cannot be dislocated from the ER membrane. (B) ATP13A1 depletion does not grossly alter the levels of MAVS in the crude cytosolic supernatant fraction. (i) Control KO cells transfected with non-targeting (nt) or ATP13A1-targeting siRNAs (siATP13A1) were fractionated as shown in Fig. 2A . Equivalent amounts of supernatant (S) and pellet (P) fractions were analysed by immunoblotting for the indicated endogenous proteins. (ii) ATP13A1 and MAVS levels in siATP13A1-treated cells relative to nt siRNA-treated cells, where protein levels were set to 1. Shown are means±s.e.m. for five biological replicates as shown in Bi. **** P <0.0001; ns, not significant (two-tailed one-sample t -test). (iii) Mean±s.e.m. of the supernatant/total ratio of MAVS levels in siATP13A1-treated cells relative to the respective ratio in nt siRNA-treated cells for five independent experiments as in Bi. Same colour data points correspond to a single biological replicate; ns, not significant (paired two-tailed t -test). (C) ATP13A1 depletion does not affect Bag6-MAVS interaction. Supernatant (S) fractions from Bi were subjected to immunoprecipitations with rabbit anti-Bag6 antibody (αBag6) or rabbit control IgG antibody. Inputs and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as loading control as well as an internal control for equal Bag6 co-immunoprecipitation potential. Arrow in Bi and C indicates full-length MAVS. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. (D) Mean±s.e.m. of MAVS levels that co-immunoprecipitate with Bag6 in siATP13A1-treated cells relative to nt siRNA-treated cells for four independent experiments as shown in C. ns, not significant (paired two-tailed t -test).

Article Snippet: Anti-Bag6 rabbit polyclonal antibodies [1:1000 for immunoblotting (IB); 1:100 for immunoprecipitation (IP)] were raised against a synthetic peptide corresponding to residues 112–130 of human Bag6 isoform 2 (GSPPGTRGPGASVHDRNAN; synthesised by Peptide Specialty Laboratories GmbH) and affinity purified (also described in ).

Techniques: Extraction, Membrane, Control, Transfection, Western Blot, Two Tailed Test, Immunoprecipitation, Derivative Assay

EMC5 depletion enhances Bag6–MAVS interaction. (A) Proposed model. Bag6 binds MAVS before its EMC-mediated integration at the ER membrane. EMC deficiency will promote Bag6 binding to the cytosolic pool of MAVS that fails to be imported into the ER membrane. (B) EMC5 depletion does not grossly alter the levels of MAVS in the crude cytosolic supernatant fraction. (i,ii) Control KO cells transfected with non-targeting (nt) or EMC5-targeting siRNAs (siEMC5) were fractionated as shown in <xref ref-type=Fig. 2A . Equivalent amounts of supernatant (S) and pellet (P) fractions were analysed by immunoblotting for the indicated endogenous proteins. Blots resulting from the same membrane are clustered together. Tubulin and OST48 serve as loading controls for the supernatant and pellet fractions, respectively. (iii) EMC subunit and MAVS levels in siEMC5-treated cells relative to nt siRNA-treated cells, where protein levels were set to 1. Shown are means±s.e.m. for three-five biological replicates as shown in Bi,ii. **** P <0.0001; ** P <0.01; ns, not significant (one-way ANOVA with Tukey's multiple comparison tests). (iv) Mean±s.e.m. of the supernatant/total ratio of MAVS levels in siEMC5-treated cells relative to the respective ratio in nt siRNA-treated cells for five independent experiments as in Bii. Same colour data points correspond to a single biological replicate; ns, not significant (paired two-tailed t -test). (C) EMC5 depletion enhances Bag6-MAVS interaction. Supernatant (S) fractions from Bi,ii were subjected to immunoprecipitations with rabbit anti-Bag6 antibody (αBag6) or rabbit control IgG antibody. Inputs and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as loading control as well as an internal control for equal Bag6 co-immunoprecipitation potential. In Bi, the EMC2 and EMC1 bands are indicated by arrows. Arrow in Bii and C indicates full-length MAVS. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. (D) Mean±s.e.m. of MAVS levels that co-immunoprecipitate with Bag6 in siEMC5-treated cells relative to nt siRNA-treated cells for four independent experiments as shown in C. * P <0.05 (paired two-tailed t -test). " width="100%" height="100%">

Journal: Journal of Cell Science

Article Title: Mitochondrial antiviral-signalling protein is a client of the BAG6 protein quality control complex

doi: 10.1242/jcs.259596

Figure Lengend Snippet: EMC5 depletion enhances Bag6–MAVS interaction. (A) Proposed model. Bag6 binds MAVS before its EMC-mediated integration at the ER membrane. EMC deficiency will promote Bag6 binding to the cytosolic pool of MAVS that fails to be imported into the ER membrane. (B) EMC5 depletion does not grossly alter the levels of MAVS in the crude cytosolic supernatant fraction. (i,ii) Control KO cells transfected with non-targeting (nt) or EMC5-targeting siRNAs (siEMC5) were fractionated as shown in Fig. 2A . Equivalent amounts of supernatant (S) and pellet (P) fractions were analysed by immunoblotting for the indicated endogenous proteins. Blots resulting from the same membrane are clustered together. Tubulin and OST48 serve as loading controls for the supernatant and pellet fractions, respectively. (iii) EMC subunit and MAVS levels in siEMC5-treated cells relative to nt siRNA-treated cells, where protein levels were set to 1. Shown are means±s.e.m. for three-five biological replicates as shown in Bi,ii. **** P <0.0001; ** P <0.01; ns, not significant (one-way ANOVA with Tukey's multiple comparison tests). (iv) Mean±s.e.m. of the supernatant/total ratio of MAVS levels in siEMC5-treated cells relative to the respective ratio in nt siRNA-treated cells for five independent experiments as in Bii. Same colour data points correspond to a single biological replicate; ns, not significant (paired two-tailed t -test). (C) EMC5 depletion enhances Bag6-MAVS interaction. Supernatant (S) fractions from Bi,ii were subjected to immunoprecipitations with rabbit anti-Bag6 antibody (αBag6) or rabbit control IgG antibody. Inputs and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as loading control as well as an internal control for equal Bag6 co-immunoprecipitation potential. In Bi, the EMC2 and EMC1 bands are indicated by arrows. Arrow in Bii and C indicates full-length MAVS. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. (D) Mean±s.e.m. of MAVS levels that co-immunoprecipitate with Bag6 in siEMC5-treated cells relative to nt siRNA-treated cells for four independent experiments as shown in C. * P <0.05 (paired two-tailed t -test).

Article Snippet: Anti-Bag6 rabbit polyclonal antibodies [1:1000 for immunoblotting (IB); 1:100 for immunoprecipitation (IP)] were raised against a synthetic peptide corresponding to residues 112–130 of human Bag6 isoform 2 (GSPPGTRGPGASVHDRNAN; synthesised by Peptide Specialty Laboratories GmbH) and affinity purified (also described in ).

Techniques: Membrane, Binding Assay, Control, Transfection, Western Blot, Comparison, Two Tailed Test, Immunoprecipitation, Derivative Assay

Stimulation with poly(I:C) compromises the Bag6–MAVS interaction. (A) Kinetics of IRF3 activation in response to cytosolic poly(I:C). Control KO cells were mock-transfected ( t =0) or transfected with poly(I:C) for various times before immunoblotting for the indicated proteins. Activation of endogenous IRF3 was assessed by induction of its phosphorylation and dimerisation. Phosphorylated IRF3 blot is representative of six independent experiments. Western blot for the detection of IRF3 dimer is representative of two independent experiments. pIRF3, phosphorylated IRF3; (IRF3)2, IRF3 dimer. (B) Stimulation with cytosolic poly(I:C) does not grossly alter the levels of MAVS in the crude cytosolic supernatant fraction. (i) Control KO cells were mock-transfected ( t =0) or transfected with poly(I:C) for various times before their fractionation as shown in <xref ref-type=Fig. 2A . The resulting supernatant (S) and pellet (P) fractions were analysed by immunoblotting for the indicated endogenous proteins. (ii,iii) Mean±s.e.m. of the (ii) pellet/total ratio and (iii) supernatant/total ratio of MAVS levels in poly(I:C)-transfected cells relative to the respective ratios in mock-transfected cells ( t =0) for six independent experiments as in Bi. ** P <0.01; ns, not significant (ordinary one-way ANOVA with Dunnett's multiple comparison tests). (C) Cytosolic poly(I:C) impairs Bag6–MAVS interaction. Supernatant fractions from Bi were subjected to immunoprecipitations with rabbit anti-Bag6 antibody (αBag6) or rabbit control IgG antibody. Inputs and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as loading control as well as internal control for comparable Bag6 binding. Arrow in MAVS blot in Bi and C indicates full-length MAVS. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. (D) Mean±s.e.m. of MAVS levels that co-immunoprecipitate with Bag6 in poly(I:C)-transfected relative to mock-transfected cells ( t =0) for six independent experiments as shown in C. * P <0.05; ns, not significant (one-way ANOVA with Dunnett's multiple comparison tests). " width="100%" height="100%">

Journal: Journal of Cell Science

Article Title: Mitochondrial antiviral-signalling protein is a client of the BAG6 protein quality control complex

doi: 10.1242/jcs.259596

Figure Lengend Snippet: Stimulation with poly(I:C) compromises the Bag6–MAVS interaction. (A) Kinetics of IRF3 activation in response to cytosolic poly(I:C). Control KO cells were mock-transfected ( t =0) or transfected with poly(I:C) for various times before immunoblotting for the indicated proteins. Activation of endogenous IRF3 was assessed by induction of its phosphorylation and dimerisation. Phosphorylated IRF3 blot is representative of six independent experiments. Western blot for the detection of IRF3 dimer is representative of two independent experiments. pIRF3, phosphorylated IRF3; (IRF3)2, IRF3 dimer. (B) Stimulation with cytosolic poly(I:C) does not grossly alter the levels of MAVS in the crude cytosolic supernatant fraction. (i) Control KO cells were mock-transfected ( t =0) or transfected with poly(I:C) for various times before their fractionation as shown in Fig. 2A . The resulting supernatant (S) and pellet (P) fractions were analysed by immunoblotting for the indicated endogenous proteins. (ii,iii) Mean±s.e.m. of the (ii) pellet/total ratio and (iii) supernatant/total ratio of MAVS levels in poly(I:C)-transfected cells relative to the respective ratios in mock-transfected cells ( t =0) for six independent experiments as in Bi. ** P <0.01; ns, not significant (ordinary one-way ANOVA with Dunnett's multiple comparison tests). (C) Cytosolic poly(I:C) impairs Bag6–MAVS interaction. Supernatant fractions from Bi were subjected to immunoprecipitations with rabbit anti-Bag6 antibody (αBag6) or rabbit control IgG antibody. Inputs and immunoprecipitates were analysed by immunoblotting for the indicated endogenous proteins. SGTA served as loading control as well as internal control for comparable Bag6 binding. Arrow in MAVS blot in Bi and C indicates full-length MAVS. Open circles on MAVS blots indicate signals derived from denatured antibody heavy and light chains. (D) Mean±s.e.m. of MAVS levels that co-immunoprecipitate with Bag6 in poly(I:C)-transfected relative to mock-transfected cells ( t =0) for six independent experiments as shown in C. * P <0.05; ns, not significant (one-way ANOVA with Dunnett's multiple comparison tests).

Article Snippet: Anti-Bag6 rabbit polyclonal antibodies [1:1000 for immunoblotting (IB); 1:100 for immunoprecipitation (IP)] were raised against a synthetic peptide corresponding to residues 112–130 of human Bag6 isoform 2 (GSPPGTRGPGASVHDRNAN; synthesised by Peptide Specialty Laboratories GmbH) and affinity purified (also described in ).

Techniques: Activation Assay, Control, Transfection, Western Blot, Phospho-proteomics, Fractionation, Comparison, Binding Assay, Derivative Assay

Working model for the role of the BAG6 complex during MAVS biogenesis. The molecular basis for the post-translational targeting and insertion of TA proteins such as MAVS into the mitochondrial outer membrane (MOM) are poorly defined (pathway 1a). Failed mitochondrial import can result in the mislocalisation of MAVS to the cytosol, where it may be recognised by one or more quality control machineries and targeted for proteasomal degradation (pathway 1b). A fraction of newly synthesised MAVS also engages the BAG6 complex either directly (pathway 3) or after transfer from SGTA (pathway 2). In the later case, SGTA may bind MAVS as its TMD leaves the ribosomal exit tunnel or after its release into the cytosol . The BAG6 complex acts upstream of MAVS ‘misinsertion’ into the ER membrane, which is most likely facilitated by the EMC (pathway 4a). It is currently unknown whether additional factors act between the BAG6 complex and the EMC insertase (pathway 4a, see ?). BAG6 binding might also enable the proteasomal degradation of mislocalised MAVS (pathway 4b). At the ER membrane, ‘mistargeted’ MAVS can be recognised by the P5A-ATPase ATP13A1 and extracted to the cytosol (pathway 5a) for either proteasomal degradation (pathway 5b) or reinsertion into the MOM via an ER-SURF pathway (pathway 5c). The access of an ER-localised pool of MAVS to ER-MOM contacts sites (MAMs) that facilitate MAVS oligomerisation and downstream signalling (pathway 6) may be modulated by the innate immune response.

Journal: Journal of Cell Science

Article Title: Mitochondrial antiviral-signalling protein is a client of the BAG6 protein quality control complex

doi: 10.1242/jcs.259596

Figure Lengend Snippet: Working model for the role of the BAG6 complex during MAVS biogenesis. The molecular basis for the post-translational targeting and insertion of TA proteins such as MAVS into the mitochondrial outer membrane (MOM) are poorly defined (pathway 1a). Failed mitochondrial import can result in the mislocalisation of MAVS to the cytosol, where it may be recognised by one or more quality control machineries and targeted for proteasomal degradation (pathway 1b). A fraction of newly synthesised MAVS also engages the BAG6 complex either directly (pathway 3) or after transfer from SGTA (pathway 2). In the later case, SGTA may bind MAVS as its TMD leaves the ribosomal exit tunnel or after its release into the cytosol . The BAG6 complex acts upstream of MAVS ‘misinsertion’ into the ER membrane, which is most likely facilitated by the EMC (pathway 4a). It is currently unknown whether additional factors act between the BAG6 complex and the EMC insertase (pathway 4a, see ?). BAG6 binding might also enable the proteasomal degradation of mislocalised MAVS (pathway 4b). At the ER membrane, ‘mistargeted’ MAVS can be recognised by the P5A-ATPase ATP13A1 and extracted to the cytosol (pathway 5a) for either proteasomal degradation (pathway 5b) or reinsertion into the MOM via an ER-SURF pathway (pathway 5c). The access of an ER-localised pool of MAVS to ER-MOM contacts sites (MAMs) that facilitate MAVS oligomerisation and downstream signalling (pathway 6) may be modulated by the innate immune response.

Article Snippet: Anti-Bag6 rabbit polyclonal antibodies [1:1000 for immunoblotting (IB); 1:100 for immunoprecipitation (IP)] were raised against a synthetic peptide corresponding to residues 112–130 of human Bag6 isoform 2 (GSPPGTRGPGASVHDRNAN; synthesised by Peptide Specialty Laboratories GmbH) and affinity purified (also described in ).

Techniques: Membrane, Control, Binding Assay