Journal: bioRxiv

Article Title: Proteome-wide multi-omics profiling of osteosarcoma transcription factor networks

doi: 10.64898/2026.03.29.714917

Figure Lengend Snippet: A) Schema of the concatenated tandem array of the consensus transcription factor response elements (catTFREs) workflow utilising two plasmids inserts C1 (designed with approximately 110 TF binding sites (TFBS) in duplicates with linkers) and C4 (reduced TFBS). Detailed TFBS are provided in Table S1A and B. Inserts were linearized by restriction enzyme digestion and biotinylated by Klenow enzyme. Biotinylated C1 and C4 were immobilized on streptavidin coated magnetic beads and incubated with nuclear extracts (NE) for detection of DNA binding proteins by mass spectrometry (MS). B) MS spectral counts of proteins enriched from NEs or by TFRE C1 and C4 pulldown. Four replicates with total count of proteins (left) and TFs only (right) from HOS (purple), U2OS (red) and MG63 (blue). All source data are provided in Table S1C-F. C) Heatmap representing the Pearson correlation of spectral counts by samples from HOS, U2OS and MG63. Scale represents low correlation in white to self-correlations as red-brown. D) Clustering of proteins by Weighted Gene Co-expression Network Analysis from MS spectral counts of NE and C1/C4 in HOS, MG63 and U2OS. Clusters I to X with the number of proteins represented by Pearson correlation across all conditions. Proteins are listed in Table S1G.

Article Snippet: The restriction digestion reactions were precipitated and biotinylated by biotinylated dUTP and dATP (Roche) using a Klenow Fragment (New England Biolabs).

Techniques: Binding Assay, Magnetic Beads, Incubation, DNA Binding Assay, Mass Spectrometry, Expressing

Journal: Tissue Barriers

Article Title: GRP75 as a functional element of cholix transcytosis

doi: 10.1080/21688370.2022.2039003

Figure Lengend Snippet: GRP75 is an interactive partner of cholix. Polarized monolayers of Caco-2 cells were exposed apically to nontoxic full-length Chx (ntChx) anchored through a C-terminal hexa-histidine sequence to 100 nm diameter magnetic beads. After 15 min, cell membranes were isolated and separated into non-magnetic and magnetic fractions. a, 1-D SDS-PAGE gel of non-magnetic and magnetic captured membrane fractions. b, 2-D gel separation of proteins present in non-magnetic and magnetic capture membrane fractions with location of spot 16 identified by mass spectrometry as GRP75. c, Pull-down (PD) using ntChx probed with antibodies to either GRP75 or human growth hormone (hGH). d, Immunoprecipitation of Caco-2 cell lysate using ntChx probed with anti-GRP75 or control antibodies. e, 2-D Western blot of magnetic capture membrane fraction probed with anti-GRP75. f, ELISA-based, neutral pH, format where bound ntChx or the control protein bovine serum albumin (BSA) was used to capture GRP75, heat shock protein 60 (HSP60), glucose-regulated protein 78 (GRP78), or HSP90.

Article Snippet: Western blotting was performed using rabbit anti-human GRP75 as primary antibody followed by using Cy3-labeled Donkey anti-rabbit secondary antibody (Jackson ImmunoResearch, 1;2500).

Techniques: Sequencing, Magnetic Beads, Isolation, SDS Page, Membrane, Mass Spectrometry, Immunoprecipitation, Control, Western Blot, Enzyme-linked Immunosorbent Assay

Journal: Tissue Barriers

Article Title: GRP75 as a functional element of cholix transcytosis

doi: 10.1080/21688370.2022.2039003

Figure Lengend Snippet: GRP75 and perlecan are functionally involved in cholix transcytosis. Expression of three proteins identified by ntChx-magnetic bead capture were suppressed using a CRISPR/cas 9-mediated knockdown protocol that targeted either GRP75, HSPG2 , or KRT8 in Caco-2 cells. Confluent monolayers of the resulting cell lines having decreased levels of a, GRP75, b, perlecan, or c, cytokeratin 8 (CT8) were evaluated for their capacity for Chx-mediated transcytosis using Chx266-hGH and for the nonspecific movement of the control protein hGH over a 60 min time period. d, Transcytosis of Chx266-hGH across confluent monolayers of parent Caco-2 cells was evaluated following a simultaneous apical application of a monoclonal antibody against GRP75 or perlecan, with an isotype antibody recognizing interleukin (IL)-10 serving as a control. Densitometry measurements of individual Western blot bands are shown for graphical comparison.

Article Snippet: Western blotting was performed using rabbit anti-human GRP75 as primary antibody followed by using Cy3-labeled Donkey anti-rabbit secondary antibody (Jackson ImmunoResearch, 1;2500).

Techniques: Expressing, CRISPR, Knockdown, Control, Western Blot, Comparison

Journal: Tissue Barriers

Article Title: GRP75 as a functional element of cholix transcytosis

doi: 10.1080/21688370.2022.2039003

Figure Lengend Snippet: GRP75 associates with cholix in apical endosomes. Immunofluorescence microscopy was performed on rat jejunum over a time course following intraluminal injection (ILI) of AMT-101. Co-localization of the human interleukin (IL)-10 element of AMT-101 with TMEM132A (a, c) or GRP75 (b, d) at 1- or 5-min post ILI. Apical (luminal) epithelial membrane (open arrow); basal epithelial cell surface-basement membrane demarcation (dashed line); lamina propria ( l-p ); goblet cell (g). Nuclei were stained with 4′,6-diamidino-2-phenylindole (DAPI; blue).

Article Snippet: Western blotting was performed using rabbit anti-human GRP75 as primary antibody followed by using Cy3-labeled Donkey anti-rabbit secondary antibody (Jackson ImmunoResearch, 1;2500).

Techniques: Immunofluorescence, Microscopy, Injection, Membrane, Staining

Journal: Tissue Barriers

Article Title: GRP75 as a functional element of cholix transcytosis

doi: 10.1080/21688370.2022.2039003

Figure Lengend Snippet: Relationship of GRP75 to GRP78 and TMEM132A. Immunofluorescence microscopy was performed on rat jejunum over a time course following intraluminal injection (ILI) of Chx266-hGH. Co-localization events detecting the human growth hormone (hGH) element of Chx266-hGH with a, TMEM132A or b, GRP78 compared to the co-localization of c, TMEM132A and GRP78 at 5 min post ILI of Chx266-hGH. Apical (luminal) epithelial membrane (open arrow); basal epithelial cell surface-basement membrane demarcation (dashed line); lamina propria ( l-p ); goblet cell (g). Nuclei were stained with 4′,6-diamidino-2-phenylindole (DAPI; blue).

Article Snippet: Western blotting was performed using rabbit anti-human GRP75 as primary antibody followed by using Cy3-labeled Donkey anti-rabbit secondary antibody (Jackson ImmunoResearch, 1;2500).

Techniques: Immunofluorescence, Microscopy, Injection, Membrane, Staining

Journal: Tissue Barriers

Article Title: GRP75 as a functional element of cholix transcytosis

doi: 10.1080/21688370.2022.2039003

Figure Lengend Snippet: GRP75 does not associate with cholix in basal vesicular structures. Immunofluorescence microscopy was performed on rat jejunum after intraluminal injection (ILI) of Chx266-hGH. The human growth hormone (hGH) element of Chx266-hGH was co-localized with early endosomal antigen 1 (EEA1; a, c) or GRP75 (b, d) at 5- or 15-min post ILI. Apical (luminal) epithelial membrane (open arrow); basal epithelial cell surface-basement membrane demarcation (dashed line); lamina propria ( l-p ); goblet cell (g). Nuclei were stained with 4′,6-diamidino-2-phenylindole (DAPI; blue).

Article Snippet: Western blotting was performed using rabbit anti-human GRP75 as primary antibody followed by using Cy3-labeled Donkey anti-rabbit secondary antibody (Jackson ImmunoResearch, 1;2500).

Techniques: Immunofluorescence, Microscopy, Injection, Membrane, Staining

Journal: Tissue Barriers

Article Title: GRP75 as a functional element of cholix transcytosis

doi: 10.1080/21688370.2022.2039003

Figure Lengend Snippet: Cholix trafficking involves LMAN1-positive compartments. Immunofluorescence microscopy was performed on rat jejunum after intraluminal injection (ILI) of Chx266-hGH. The human growth hormone (hGH) element of Chx266-hGH was co-localized with a, early endosomal antigen 1 (EEA1) or b, LMAN1 at 5 min post ILI. c, Co-localization of EEA1 and LMAN1 at 5 min post ILI. Co-localization of hGH with d, GRP75 or e, LMAN1 at 15 min post ILI of Chx266-hGH. f, Co-localization of GRP75 and LMAN1 at 15 min post ILI of Chx266-hGH. Apical (luminal) epithelial membrane (open arrow); basal epithelial cell surface-basement membrane demarcation (dashed line); lamina propria ( l-p ); goblet cell (g). Nuclei were stained with 4′,6-diamidino-2-phenylindole (DAPI; blue).

Article Snippet: Western blotting was performed using rabbit anti-human GRP75 as primary antibody followed by using Cy3-labeled Donkey anti-rabbit secondary antibody (Jackson ImmunoResearch, 1;2500).

Techniques: Immunofluorescence, Microscopy, Injection, Membrane, Staining

Journal: Tissue Barriers

Article Title: GRP75 as a functional element of cholix transcytosis

doi: 10.1080/21688370.2022.2039003

Figure Lengend Snippet: GRP75 intersects with furin differently than with LMAN1. Immunofluorescence microscopy was performed on rat jejunum after intraluminal injection (ILI) of Chx266-hGH. The human growth hormone (hGH) element of Chx266-hGH was co-localized with a, furin or b, GRP75 at 15 min post ILI. c, Co-localization of furin and GRP75 at 15 min post ILI. Co-localization of hGH with d, furin or e, LMAN1 at 15 min post ILI of Chx266-hGH. f, Co-localization of furin and LMAN1 at 15 min post ILI of Chx266-hGH. Apical (luminal) epithelial membrane (open arrow); basal epithelial cell surface-basement membrane demarcation (dashed line); lamina propria ( l-p ); goblet cell (g). Nuclei were stained with 4′,6-diamidino-2-phenylindole (DAPI; blue).

Article Snippet: Western blotting was performed using rabbit anti-human GRP75 as primary antibody followed by using Cy3-labeled Donkey anti-rabbit secondary antibody (Jackson ImmunoResearch, 1;2500).

Techniques: Immunofluorescence, Microscopy, Injection, Membrane, Staining

Journal: Tissue Barriers

Article Title: GRP75 as a functional element of cholix transcytosis

doi: 10.1080/21688370.2022.2039003

Figure Lengend Snippet: Diagram of events associated with cholix apical to basal transcytosis with interaction partners. Highlighted steps are explained in the text with greater detail. (1) Cholix enters at the apical plasma membrane in the microvilli area where it interacts with TMEM132A and furin. (2) Cholix enters an early endosomal compartment where it traffics preferentially to a late endosome rather than a recycling pathway. (3) Instead of continuing along the lysosomal degradation pathway, cholix interacts with GRP75 and moves to a sorting endosome. (4) Reorganization of LMAN1 from the endoplasmic reticulum intermediate Golgi complex (ERGIC) to apical sorting vesicles. (5) In this location, LMAN1 can intersect with cholix delivered to this site with furin and GRP75. (6) LMAN1 and furin appear to return with cholix to a supranuclear region of the cell consistent with location of the ERGIC. (7) Reorganization of LMAN1 from the ERGIC to the basal vesicular compartment provides a route for cholix to this region of the cell. (8) Cholix in complex with LMAN1 enters sorting endosomes in the basal vesicular compartment. (9) Within basal sorting endosomes, cholix/LMAN1 intersects with perlecan in a recycling endosome, which delivers it to the basal plasma membrane, resulting in cholix exocytosis and completion of the apical to basal transcytosis process. (10) Perlecan recycles to the basal sorting endosome where it can engage cholix trafficked to this site with LMAN1. (11) Unlike in the apical vesicular compartment, GRP75 and furin present in the basal vesicular compartment are not associated with cholix in this region of enterocytes.

Article Snippet: Western blotting was performed using rabbit anti-human GRP75 as primary antibody followed by using Cy3-labeled Donkey anti-rabbit secondary antibody (Jackson ImmunoResearch, 1;2500).

Techniques: Clinical Proteomics, Membrane