AMPK directly phosphorylates ULK1 to connect energy sensing to autophagy/mitophagy, opposing mTOR.
| Evidence tier | D Mechanistic / in vitro / review |
| Study type | 5 - Mechanistic / In Vitro |
| Model system | Mammalian cells |
| Journal | Science |
| Year | 2010 |
| Peer reviewed | Yes |
| Source | DOI 10.1126/science.1196371 · PMID 21205641 · Free full text (PMC3030664) |
Adenosine monophosphate-activated protein kinase (AMPK) is a conserved sensor of intracellular energy activated in response to low nutrient availability and environmental stress. In a screen for conserved substrates of AMPK, we identified ULK1 and ULK2, mammalian orthologs of the yeast protein kinase Atg1, which is required for autophagy. Genetic analysis of AMPK or ULK1 in mammalian liver and Caenorhabditis elegans revealed a requirement for these kinases in autophagy. In mammals, loss of AMPK or ULK1 resulted in aberrant accumulation of the autophagy adaptor p62 and defective mitophagy. Reconstitution of ULK1-deficient cells with a mutant ULK1 that cannot be phosphorylated by AMPK revealed that such phosphorylation is required for mitochondrial homeostasis and cell survival during starvation. These findings uncover a conserved biochemical mechanism coupling nutrient status with autophagy and cell survival.
| Intervention | Genetic/biochemical (AMPK–ULK1) |
| Target | AMPK / ULK1 / mTORC1 |
| Model | Mammalian cells (+ C. elegans) |
| Effect | AMPK phosphorylates ULK1 to connect energy sensing to autophagy/mitophagy |