Journal: PLoS Pathogens

Article Title: STAT and Janus kinase targeting by human herpesvirus 8 interferon regulatory factor in the suppression of type-I interferon signaling

doi: 10.1371/journal.ppat.1010676

Figure Lengend Snippet: (A-C) Flag-tagged STAT1 (A) or IRF9 (C) or CBD-tagged STAT2 (B) were expressed in 293T cells transfected with the respective expression plasmids and either vIRF-1 (virf1) or empty (-) expression vector; replicates were either left untreated (mock) or treated with IFNβ (10 ng/ml) for 24 h. Flag/CBD-tagged proteins were then immuno/affinity-precipitated from cell lysates, and coprecipitated ISGF3 proteins were detected by immunoblotting. Diagrams below the panels illustrate the main findings from each experiment. (D-E) Serial coprecipitations of STAT1 and STAT2 (D), STAT1 and IRF9 (E), and IRF9 and STAT2 (F), respectively Flag- and CBD-tagged, from lysates of transfected 293T cells expressing vIRF-1 (virf1) or cotransfected with empty vector (-). All transfectants were treated with IFNβ for 24 h prior to harvesting. First (Flag IP) and second (CBD AP) precipitates (Precip. 1, Precip. 2) were analyzed by immunoblotting for the tagged “bait” proteins, the third (endogenous) ISGF3 protein (including phosphorylated and total STAT1 and STAT2), and vIRF-1; lysates were immunoblotted for expression of input proteins. Illustrated below each panel of blots are the main findings. (G) Disruption by vIRF-1 of STAT1-STAT2 complexes isolated by Flag-IP (STAT1) and CBD-AP (STAT2) from IFNβ-treated transfected 293T cells. Immunoprecipitated material from vIRF-1-Flag (virf1) or empty control (cntl) vector-transfected cells was applied in two concentrations (1x, 2x) to dual-precipitation-derived STAT1/STAT2 complexes, and then mixtures were subjected to re-precipitation with chitin beads (binding STAT2-CBD). STAT1 and vIRF-1 associated with re-precipitated STAT2-CBD were identified by immunoblotting. Relative levels of co-precipitated STAT1, normalized to affinity-sedimented STAT2, are shown below the STAT1 blot (cntl/1x value set at 1). (H) An equivalent experiment was carried out using GST-fused recombinant vIRF-1 (virf1) or GST (negative control) to challenge STAT1 interaction with STAT2 in STAT1/STAT2 hetero-complexes isolated by IP/AP dual precipitations from IFNβ-treated 293T cells. Endogenous IRF9 interaction with STAT1/2 and competition by vIRF-1 were also monitored. Relative levels and integrities of the recombinant proteins are shown in the Coomassie-stained gel (right); arrowheads indicate the positions of the full-length proteins.

Article Snippet: Primary antibodies used for immunoblotting were: S (Abcam, catalog number ab184223); CBD (New England BioLabs, E8034S); Flag (Sigma, F1804); β-actin (Sigma, A5316); GAPDH (Invitrogen, TAB1001); vIRF-1 (rabbit polyclonal antiserum, provided by Dr. Gary Hayward); STAT1, pSTAT1, IRF9, His 6 , GST and p53 from Santa Cruz Biotechnologies (catalog numbers sc464, sc-365893, sc-8394, sc-803, sc-138, and sc-126, respectively); STAT2 and pSTAT2 from Cell Signaling Technology (catalog numbers 72604 and 4441).

Techniques: Transfection, Expressing, Plasmid Preparation, Western Blot, Isolation, Immunoprecipitation, Derivative Assay, Binding Assay, Recombinant, Negative Control, Staining

Journal: PLoS Pathogens

Article Title: STAT and Janus kinase targeting by human herpesvirus 8 interferon regulatory factor in the suppression of type-I interferon signaling

doi: 10.1371/journal.ppat.1010676

Figure Lengend Snippet: (A) TYK2-S and STAT2-CBD were expressed with (virf1) or without (-) vIRF-1 in transfected 293T cells. Cell lysates and S-protein affinity-precipitates were assessed for input protein expression and sedimentation by immunoblotting with CBD (STAT2), vIRF-1, and S-tag (TYK2) antibodies. Affinity-precipitated TYK-2-S was probed with phospho-tyrosine (PY)-specific antibody to identify the active, autophosphorylated form of the kinase. Dotted lines indicate lane deletions from single membranes; the arrowhead and asterisk indicate CBD-specific (STAT2) band and remnant S-tag signal (after blot stripping), respectively. (B) An equivalent experiment was performed to assess vIRF-1 effects on JAK1 autophosphorylation and association with STAT2. Here, STAT2 antibody was used to detect endogenous protein. Arrowheads indicate JAK1-S (~130 kDa). (C) ISRE-luciferase reporter assay to assess vIRF-1 inhibition of TYK2-mediated signal transduction in 293T cells cotransfected with TYK2-expression and reporter plasmids and either vIRF-1 (virf1) or empty (-) expression vectors. Average values from duplicate samples for each condition are shown; error bars indicate standard deviations from the means. Statistical significance (P) was determined by student t-test (two-tailed, unpaired). (D) IFNAR1-S-based coprecipitation assay to test the influence of vIRF-1 (virf1), relative to empty-vector (-) transfection, on STAT2-receptor association, following IFNβ stimulation for 30 min. STAT2-CBD vector cotransfection provided expression of STAT2 above endogenous levels, to facilitate detection. (E) Effect of vIRF-1 on IFNβ receptor (IFNAR1) activation and association with TYK2. Transfectants expressing vIRF-1 or containing empty vector (-, negative control) and expressing, or lacking (-), introduced IFNAR1-CBD were left untreated (mock) or treated with IFNβ (10 ng/ml) for 24 h; TYK2-S was expressed in a subset of the transfected cultures. Cell lysates were analyzed for expression of the introduced proteins, and IFNAR1-CBD was affinity-precipitated from a subset of lysates to assess interaction of the receptor with TYK2 in response to vIRF-1. The numbers below the CBD blots show relative levels (-/+ vIRF-1) of IFNβ-induced lower IFNAR1 band (arrowheads) to total IFNAR1 (top plus bottom bands) from TYK2-overexpressing transfectants (+TYK2) and those devoid of TYK2 expression plasmid (-TYK2); values in the absence (-) of vIRF-1 are set at 1. For all precipitations (panels A, B, D and E), cultures were treated with DSP (2 mM, 30 min.) immediately prior to cell harvest, to stabilize targeted complexes.

Article Snippet: Primary antibodies used for immunoblotting were: S (Abcam, catalog number ab184223); CBD (New England BioLabs, E8034S); Flag (Sigma, F1804); β-actin (Sigma, A5316); GAPDH (Invitrogen, TAB1001); vIRF-1 (rabbit polyclonal antiserum, provided by Dr. Gary Hayward); STAT1, pSTAT1, IRF9, His 6 , GST and p53 from Santa Cruz Biotechnologies (catalog numbers sc464, sc-365893, sc-8394, sc-803, sc-138, and sc-126, respectively); STAT2 and pSTAT2 from Cell Signaling Technology (catalog numbers 72604 and 4441).

Techniques: Transfection, Expressing, Sedimentation, Western Blot, Stripping, Luciferase, Reporter Assay, Inhibition, Transduction, Two Tailed Test, Plasmid Preparation, Cotransfection, Activation Assay, Negative Control

Journal: The Journal of Cell Biology

Article Title: Sequential dynein effectors regulate axonal autophagosome motility in a maturation-dependent pathway

doi: 10.1083/jcb.202010179

Figure Lengend Snippet: Antibodies

Article Snippet: Anti-CBD , E80345 (New England Biolabs) , WB @ 1:800 , .

Techniques: Western Blot, Proximity Ligation Assay