α-SNAP inhibits AMPK signaling to reduce mitochondrial biogenesis and dephosphorylates Thr172 in AMPKα in vitro

摘要

The AMP-activated protein kinase (AMPK) regulates metabolism in normal and pathological conditions and responds to nutrients, hormones, anti-diabetic drugs and physical exercise. AMPK is activated by the kinase LKB1 and inactivated by phosphatases whose identities remain uncertain. Here we show that AMPK associates with α-SNAP , an adapter that enables disassembly of cis-SNARE complexes formed during membrane fusion. Knockdown of α-SNAP activates AMPK to phosphorylate its endogenous substrates acetyl CoA carboxylase and Raptor , and provokes mitochondrial biogenesis. AMPK phosphorylation is rescued from α-SNAP RNA interference by LKB1 knockdown or expression of wild-type but not mutated α-SNAP . Recombinant wild-type but not mutated α-SNAP dephosphorylates pThr172 in AMPKα in vitro . Overexpression of wild-type but not mutated α-SNAP prevents AMPK activation in cells treated with agents to elevate AMP concentration. The mouse α-SNAP mutant hyh (hydrocephalus with hop gait) shows enhanced binding and inhibition of AMPK. By negatively controlling AMPK, α-SNAP therefore potentially coordinates membrane trafficking and metabolism.