Figure 5. GSK3α activation inhibits mitochondrial fission through phosphorylation of Drp1 at Ser637 in Sertoli cells. (A) Representative electron microscopic images of mitochondrial ultrastructure in TM4 cells treated with HS or GSK3α inhibitor. Arrows indicate mitochondria. Scale bars=1 μm. (B) Histogram showing ΔΨm in TM4 cells by JC-1 staining and flow cytometric analysis (C) Western blots and histogram showing the protein levels of Ser637-Drp1 in TM4 cells treated with HS or GSK3α inhibitor. (D) Representative immunofluorescence images of mitochondria (red) in TM4 cells treated with HS or GSK3α inhibitor. (E-G) Immunoprecipitation of Ser637-Drp1 with anti-GSK3α in TM4 cell followed by immunoblotting analysis to demonstrate the stimulatory effects of HS on the interaction between GSK3α and Ser637-Drp1. Con: control; HS: heat shock; SB: SB216763. Scale bars=1 μm. Values are expressed as the mean±SEM, n=6. Values with different superscripts are significantly different from each other (P<0.05).