Regulation of AMPK. AMPK (blue) becomes activated under conditions of high AMP/ATP (metabolic depletion), or in response to the hormones leptin and adiponectin [1, 25, 26]. Under these circumstances, AMP binds to AMPK, facilitating phosphorylation at Thr172 and activation, in a reaction catalyzed by the LKB1-STRAD-MO25 complex (AMPKK; red). AMP also prevents dephosphorylation and deactivation of AMPK and serves as an allosteric activator of AMPK. See text for further details.