The FOX transcription factor Hcm1 regulates oxidative metabolism in response to early nutrient limitation in yeast. Role of Snf1 and Tor1/Sch9 kinases

摘要: Within Saccharomyces cerevisiae, Hcm1is a member of the forkhead transcription factor family with role in chromosome organization. Our group recently described its involvement mitochondrial biogenesis and stress resistance, reports here that Hcm1 played adaptation to respiratory metabolism when glucose or nitrogen was decreased. Regulation activity occurs at least three ways: i) protein quantity, ii) subcellular localization, iii) transcriptional activity. Transcriptional measured using reporter gene fused promoter contains binding site for Hcm1. We also analyzed levels several genes whose expression is known be regulated by main kinases respond nutrients. Lack sucrose-nonfermenting (Snf1) kinase increases cytoplasmic localization Hcm1, whereas Δtor1 cells showed mild increase nuclear In vitro experiments Snf1 clearly phosphorylates while Sch9 exerts milder phosphorylation. Although vitroTor1 does not directly phosphorylate vivo rapamycin treatment conclude participates from fermentation during nutrient scarcity. According our hypothesis, decrease, This results shift cytoplasm nucleus increased involved respiration, use alternative energy sources, NAD synthesis oxidative resistance.