Metabolism

Serine/threonine kinase AMPK upregulates glucose uptake by promoting the expression and function of glucose transporters. AMPK is activated by increased AMP/ATP ratio, resulting from cellular and environmental stress, e.g. low glucose, heat shock, hypoxia and ischemia. AMPK activation positively modulates signaling transductions that refill ATP levels. Moreover, it also stimulates catabolic processes such as fatty acid oxidation and glycolysis through inhibition of ACC and activation of PFK2. AMPK negatively regulates various proteins which are important to ATP-consuming mechanisms, e.g. mTORC2, glycogen synthase, SREBP-1, and TSC2, causing the downregulation/inhibition of gluconeogenesis and glycogen, lipid and protein synthesis.