PKM2 promotes mitochondrial OXPHOS. (A) Effects of PKM2 on extracellular acidification rate (ECAR) in H1299 and HepG2 cells. Top panels: ECAR traces were obtained using a Seahorse XF96 Analyzer. Bottom panels: Statistical analyses of glycolysis, glycolytic capacity and glycolytic reserve in ECAR. 2-DG, 2-deoxy-D-glucose. (B) Immunoblots showing the expression of wild type (WT) PKM2 or mutants of PKM2 in H1299 and HepG2 cells. The right-hand lane (labeled MEF) contains TCL of mouse embryonic fibroblasts. (C) Effects of PKM2 on oxygen consumption rate (OCR) in H1299 and HepG2 cells. Top panels: OCR traces were obtained using a Seahorse XF96 Analyzer. Bottom panels: Statistical analyses of baseline respiratory capacity, ATP-coupled respiratory capacity, maximum respiratory capacity and reserve respiratory capacity in OCR. FCCP, carbonyl cyanide-4 (trifluoromethoxy) phenylhydrazone. A & R, antimycin plus rotenone. (D) Relative PKM2 activity in H1299 and HepG2 cells. NS, no statistical significance. PKM2/4A is the R73A/K270A/D296A/T328A mutant of PKM2. Data are shown as mean ± s.e.m. *P < 0.05, **P < 0.01, ***P < 0.001, n = 6