The alternative activity of nuclear PHGDH contributes to tumor growth under nutrient stress. The alternative activity of nuclear PHGDH contributes to tumor growth under nutrient stress

Here we show under glucose deficiency PHGDH is phosphorylated by p38 at Ser371, which promotes the cytosol-localized PHGDH translocation into the nucleus. Meanwhile, AMPK concurrently phosphorylates PHGDH-Ser55 and selectively increases PHGDH catalytic activity against malate oxidation, thus pushing the reduction of NAD+ towards NADH generation. In the nucleus, the altered PHGDH activity positively regulates NADH/NAD+ ratio and thus restricts NAD+ level, and thereby leads to repression of NAD+-dependent PARP1 activity. Moreover, PHGDH is found to be associated with Ser73-phosphorylated c-Jun and specifically inhibits PARP1-mediated c-Jun poly(ADP-ribosyl)ation, which accordingly led to the impaired c-Jun transcriptional activity against genes expression linking to cell growth inhibition. Overall design: Transcriptome profile analysis in WT rPHGDH and rPHGDH S371A or rPHGDH S55A SW1990 cells under glucose deprivation