Ulk1 is a serine/threonine kinase and the mammalian functional homolog of yeast Atg1. It acts at the initiation step of autophagy and forms a complex with mAtg13, FIP200 and Atg101. Assembly of this complex is independent of mTOR signaling, indicating the regulation of autophagy initiation in mammals is different from that in yeast. In a recent study, we reported that Ulk1 can be phosphorylated by mTOR and AMPK kinases. AMPK associates with Ulk1 in nutrient-dependent manner. Rapid dissociation between Ulk1 and AMPK primes cells for fast autophagy induction upon nutrient withdrawal. These studies show that both mTOR and AMPK directly regulate Ulk1 and coordinate the mammalian autophagy initiation.
L Shang, S Chen, F Du, S Li, L Zhao, X Wang. Nutrient starvation elicits an acute autophagic response mediated by Ulk1 dephosphorylation and its subsequent dissociation from AMPK. Proc Natl Acad Sci U S A 2011; 108: 4788- 93.
PMID: 21383122 DOI: 10.1073/pnas.1100844108