Fig. 4: PJA1 inhibits docetaxel-induced mitochondrial damage via the PGAM5-DRP1 axis.
a Diagram showing that PGAM5 recruits DRP1 and dephosphorylates DRP1 at S637 site. b IF staining revealed the cellular localisation of endogenous DRP1 (blue), PGAM5 (green) and mitochondria (red). Scale bars, 5 μm. c Co-IP with an anti-DRP1 antibody revealed the endogenous associations of DRP1 with PJA1 and PGAM5 in NPC cells. d, e Protein levels of total DRP and pDRP1ser637 in HONE1 cells transfected with the shCtrl or sh-PJA1s plasmids alone (d) or together with the Myc-PGAM5-WT or the K88R mutant plasmids (e). f Representative fluorescence images of mitochondria in NPC cells transfected with the shCtrl or sh-PJA1s plasmids and exposed to docetaxel (10 nM). Scale bar, 1 μm. More than 50 cells were counted to determine the proportions of tubular and fragmented mitochondria (mean ± s.d., one-way ANOVA). g–i The mitochondrial membrane potential (g), the production of ATP (h) and mROS (i) measured by flow cytometry in NPC cells transfected with the shCtrl or sh-PJA1s plasmids and exposed to Doc (10 nM) (mean ± s.d., one-way ANOVA). j Levels of cytochrome c in the cytoplasmic (Cyto) and mitochondrial (Mito) fractions of lysates from NPC cells transfected with the shCtrl or sh-PJA1s plasmids and exposed to Doc (10 nM). k Representative images of mitochondria in HONE1 cells transfected with the shCtrl or sh-PJA1 plasmids together with shNC or shPGAM5 plasmids, and exposed to Doc (10 nM). Scale bar, 1 μm. More than 50 cells were counted to determine the proportions of tubular and fragmented mitochondria (mean ± s.d., one-way ANOVA). l, m Flow cytometric analysis of mitochondrial membrane potential (l) and the production of mROS (m) in NPC cells transfected with the shCtrl or sh-PJA1 plasmids together with shNC or shPGAM5 plasmids, and exposed to Doc (10 nM) (mean ± s.d., one-way ANOVA). One-way ANOVA with Dunnett’s multiple comparisons test; n (f–i, k–m) = 3 independent experiments. Source data are provided as a Source Data file.
