Description
Mammalian ULK1 (unc-51 like kinase 1) and ULK2, Caenorhabditis elegans UNC-51, and Drosophila melanogaster Atg1 are serine/threonine kinases that regulate flux through the autophagy pathway in response to various types of cellular stress.ULK1 and ULK2 all have different tissue-specific expressions partially contributing to diverse and ULK-specific interaction networks in various tissues.ULK1 (or its close family member ULK2) interacts with several other proteins to form a large complex that is required for the formation of an autophagosome. The other proteins that complex with ULK1/ULK2 include ATG13, ATG101, and RB1CC1 (FIP200/ATG17).AMPK, activated during low nutrient conditions, directly phophorylates ULK1 at multiple sites including Ser317, Ser555, and Ser777. Conversely, mTOR, which is a regulator of cell growth and is an inhibitor of autophagy, phosphorylates ULK1 at Ser757 and disrupts the interaction between ULK1 and AMPK.