Fig 2: Immunofluorescence images of integrin alpha-7 (ITGA7) co-localized with alpha-synuclein (a-syn) in C2C12 cells. Cell regions were immunofluorescently labeled with anti-ITGA7 (b,g) and anti-a-syn (a,f) antibodies using Rhodamine Avidin (a,f; red), followed by Fluorescein Avidin (b,g; green). Middle panels (c,h) show merged images of individual a-syn (a,f) and ITGA7 (b,g) panels. Compared with the control (CTL) group, the expression of ITGA7 decreases and the expression of a-syn increases in the MPP+ group (h,i), and merged expression of ITGA7 and a-syn can be observed in the CTL group (c,d). (d) and (i) are enlarged images of the squares in (c) and (h). (e,j) displays the image merged with DAPI. White arrows indicate regions of interest.

Fig 3: TMEM182 directly interacts with ITGB1. (A) Lysates of chicken primary myoblasts overexpressing TMEM182 or EGFP control were immunoprecipitated with TMEM182 antibody and then Western blotted with anti‐β1 integrin (anti‐ITGB1), anti‐TMEM182, and anti‐tubulin. (B) Lysates of chicken gastrocnemius muscle were immunoprecipitated with ITGB1 antibody and then Western blotted with anti‐ITGB1, anti‐TMEM182, and anti‐ITGA7. (C) Flag vector or FLAG‐ITGB1 was transfected into chicken primary myoblasts and immunoprecipitated with anti‐FLAG‐agarose beads followed by eluting with FLAG peptide. GST‐TMEM182 or control glutathione‐S‐transferase (GST) protein was incubated with purified FLAG‐ITGB1, FLAG peptide, or bovine serum albumin for pull‐down assay and then Western blotted with FLAG antibody. The amounts of GST and GST‐TMEM182 used in this experiment were indicated by immunoblotting with anti‐GST antibody (middle panel). (D) Schematic diagram of chicken TMEM182 and its putative domains. (E) FLAG‐tagged ITGB1 or domain constructs as shown in (D) was transfected into chicken myoblast and purified by using anti‐FLAG‐agarose beads (bottom panel). GST or GST‐TMEM182 fusion protein was incubated with purified FLAG‐tagged proteins for direct pull‐down assay (top panel). (F) The predicted transmembrane helices of chicken TMEM182 protein. (G–H) FLAG‐tagged TMEM182 or mutant constructs was transfected into chicken myoblast and purified by using anti‐FLAG‐agarose beads (bottom panel). GST or GST‐ITGB1 fusion protein was incubated with purified FLAG‐tagged proteins for direct pull‐down assay (top panel).

Fig 4: Representative images of muscle integrin alpha-7 (ITGA7) expression in a chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson’s disease mouse model. ITGA7 expression increases in the control (CTL) group (a,b) and decreases in the MPTP group (c, d). Images of (b) and (d) are magnified images of squares in (a) and (c). Western immunoblot analyses (e,f) show that ITGA7 expression is decreased in the MPTP group. * p < 0.05 compared to CTL. All values are expressed as mean ± standard error, and statistical analyses were performed using the Student’s t-test. Black arrows indicate regions of interest.

Fig 5: Western immunoblot analysis shows that administration of ITGA7 siRNA reduced ITGA7 expression in C2C12 cells (a). It also shows that a-synuclein (a-syn) expression was increased (b). ITGA7 siRNA treatment (10 nM for 24 h); ITGA7 siRNA treatment (100 nM for 24 h). * Negative control (NC) siRNA treatment (100 nM for 24 h). * p< 0.05, ** p< 0.005 compared to NC. All values were expressed as mean ± standard error, and statistical analysis was performed using Student’s t-test.