Department of Pharmacology, University of California San Diego, La Jolla, CA, USA.
Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA.
Nat Commun. 2022 Jul 5;13(1):3856. doi: 10.1038/s41467-022-31190-x.
AMP-activated protein kinase (AMPK) is a master regulator of cellular energetics which coordinates metabolism by phosphorylating a plethora of substrates throughout the cell. But how AMPK activity is regulated at different subcellular locations for precise spatiotemporal control over metabolism is unclear. Here we present a sensitive, single-fluorophore AMPK activity reporter (ExRai AMPKAR), which reveals distinct kinetic profiles of AMPK activity at the mitochondria, lysosome, and cytoplasm. Genetic deletion of the canonical upstream kinase liver kinase B1 (LKB1) results in slower AMPK activity at lysosomes but does not affect the response amplitude at lysosomes or mitochondria, in sharp contrast to the necessity of LKB1 for maximal cytoplasmic AMPK activity. We further identify a mechanism for AMPK activity in the nucleus, which results from cytoplasmic to nuclear shuttling of AMPK. Thus, ExRai AMPKAR enables illumination of the complex subcellular regulation of AMPK signaling.
腺苷酸活化蛋白激酶 (AMPK) 是细胞能量代谢的主调控因子，通过磷酸化细胞内大量底物来协调代谢。但是，AMPK 活性如何在不同的亚细胞位置受到调节，以实现对代谢的精确时空控制尚不清楚。在这里，我们展示了一种灵敏的、单荧光素 AMPK 活性报告器 (ExRai AMPKAR)，它揭示了 AMPK 在线粒体、溶酶体和细胞质中的活性的不同动力学特征。经典上游激酶肝激酶 B1 (LKB1) 的基因缺失导致溶酶体中的 AMPK 活性降低，但不会影响溶酶体或线粒体中的反应幅度，这与 LKB1 对于细胞质中最大 AMPK 活性的必要性形成鲜明对比。我们进一步确定了核内 AMPK 活性的机制，这是由 AMPK 从细胞质到核内的穿梭引起的。因此，ExRai AMPKAR 能够阐明 AMPK 信号转导的复杂亚细胞调节。
