State Key Laboratory for Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, 361102 Fujian, China.
State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, PKU-IDG/McGovern Institute for Brain Research, Peking University, 100871 Beijing, China.
Cell Metab. 2019 Sep 3;30(3):508-524.e12. doi: 10.1016/j.cmet.2019.05.018. Epub 2019 Jun 13.
Fructose-1,6-bisphosphate (FBP) aldolase links sensing of declining glucose availability to AMPK activation via the lysosomal pathway. However, how aldolase transmits lack of occupancy by FBP to AMPK activation remains unclear. Here, we show that FBP-unoccupied aldolase interacts with and inhibits endoplasmic reticulum (ER)-localized transient receptor potential channel subfamily V, inhibiting calcium release in low glucose. The decrease of calcium at contact sites between ER and lysosome renders the inhibited TRPV accessible to bind the lysosomal v-ATPase that then recruits AXIN:LKB1 to activate AMPK independently of AMP. Genetic depletion of TRPVs blocks glucose starvation-induced AMPK activation in cells and liver of mice, and in nematodes, indicative of physical requirement of TRPVs. Pharmacological inhibition of TRPVs activates AMPK and elevates NAD levels in aged muscles, rejuvenating the animals' running capacity. Our study elucidates that TRPVs relay the FBP-free status of aldolase to the reconfiguration of v-ATPase, leading to AMPK activation in low glucose.
果糖-1,6-二磷酸醛缩酶(FBP)通过溶酶体途径将葡萄糖可用性下降的感应与 AMPK 激活联系起来。然而,醛缩酶如何将 FBP 的空位传递给 AMPK 激活仍不清楚。在这里,我们表明,未被 FBP 占据的醛缩酶与内质网(ER)定位的瞬时受体电位通道亚家族 V 相互作用并抑制其活性,从而抑制低葡萄糖条件下的钙释放。在 ER 和溶酶体之间的接触部位钙的减少使被抑制的 TRPV 能够与溶酶体 v-ATP 酶结合,然后招募 AXIN:LKB1 独立于 AMP 激活 AMPK。TRPV 的基因缺失会阻止细胞和小鼠肝脏中葡萄糖饥饿诱导的 AMPK 激活,在线虫中也是如此,表明 TRPV 具有物理需求。TRPV 的药理学抑制会激活 AMPK 并提高衰老肌肉中的 NAD 水平,从而恢复动物的跑步能力。我们的研究阐明了 TRPV 将醛缩酶的无 FBP 状态传递给 v-ATP 酶的重新配置,从而在低葡萄糖条件下激活 AMPK。