Department of Microbiology, Immunology and Cancer Biology, Center for Cell Signaling, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA.
Nat Commun. 2013;4:1559. doi: 10.1038/ncomms2565.
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.
AMP 激活的蛋白激酶（AMPK）在正常和病理条件下调节代谢，并对营养物质、激素、抗糖尿病药物和体育锻炼作出反应。AMPK 被激酶 LKB1 激活，被其身份仍不确定的磷酸酶失活。在这里，我们发现 AMPK 与 α-SNAP 结合，α-SNAP 是一种衔接蛋白，能够使在膜融合过程中形成的顺式 SNARE 复合物解体。α-SNAP 的敲低激活 AMPK，使其磷酸化其内源性底物乙酰辅酶 A 羧化酶和 Raptor，并引发线粒体生物发生。α-SNAP RNA 干扰的 AMPK 磷酸化可通过 LKB1 敲低或野生型而非突变型 α-SNAP 的表达得到挽救。重组野生型而非突变型 α-SNAP 在体外使 AMPKα 上的 pThr172 去磷酸化。在用升高 AMP 浓度的药物处理的细胞中，过表达野生型而非突变型 α-SNAP 可防止 AMPK 的激活。小鼠 α-SNAP 突变体 hyh（脑积水伴跳跃步态）显示出增强的 AMPK 结合和抑制作用。因此，通过负调控 AMPK，α-SNAP 可能协调膜运输和代谢。
