Fig. 2

Effects of AKT activation on metabolic pathways during iPSC induction, as assessed by metabolomic analyses. a Volcano plot representing all metabolites quantified by ion chromatography–tandem mass spectrometry. For every metabolite, the log₂ fold change of AKT-activated versus AKT-nonactivated cells was plotted against the − log₁₀ false discovery rate adjusted p value (n = 3). Colored and black dots depict significantly higher or lower levels of metabolites in AKT-activated cells than in AKT-nonactivated cells, and gray dots represent metabolites showing no significant difference (p < 0.05). Each color represents a metabolic process related to processes such as glycolysis, the pentose phosphate pathway, the TCA cycle or nucleotide biosynthesis, as indicated on the upper right. b Fold changes in metabolites involved in the TCA cycle, as quantified by ion chromatography–tandem mass spectrometry (n = 3). Metabolites not containing ¹³C were derived from intracellularly accumulated substrates or extracellular nonglucose substrates, whereas ¹³C-containing metabolites were derived from extracellular glucose. The levels of non-¹³C-containing and ¹³C-containing metabolites in AKT-nonactivated cells (− 4OHT) were set to 1. c Fold change in cytosolic αKG, as quantified by ion chromatography–tandem mass spectrometry (Rep 1–4; 4 independent experiments). Western blots with antibodies against HSP60 (mitochondrial marker) and α-tubulin (cytosolic marker) indicated the successful exclusion of mitochondria from the cytoplasmic fraction (c) of the whole-cell lysate (w)