Serine/threonine-protein kinase involved in autophagy in response to starvation. Acts upstream of phosphatidylinositol 3-kinase PIK3C3 to regulate the formation of autophagophores, the precursors of autophagosomes. Part of regulatory feedback loops in autophagy: acts both as a downstream effector and a negative regulator of mammalian target of rapamycin complex 1 (mTORC1) via interaction with RPTOR. Activated via phosphorylation by AMPK, also acts as a negative regulator of AMPK through phosphorylation of the AMPK subunits PRKAA1, PRKAB2 and PRKAG1. May phosphorylate ATG13/KIAA0652, FRS2, FRS3 and RPTOR; however such data need additional evidences. Not involved in ammonia-induced autophagy or in autophagic response of cerebellar granule neurons (CGN) to low potassium concentration. Plays a role early in neuronal differentiation and is required for granule cell axon formation: may govern axon formation via Ras-like GTPase signaling and through regulation of the Rab5-mediated endocytic pathways within developing axons. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Component of a complex consisting of ATG13/KIAA0652, ULK1 and RB1CC1/FIP200. Interacts (via C-terminus) with ATG13/KIAA0652. Associates with the mammalian target of rapamycin complex 1 (mTORC1) through an interaction with RPTOR (By similarity). Interacts with SYNGAP1. Localizes to pre-autophagosomal membrane. Widely expressed. The CTD-like region mediates membrane-binding and incorporation into large protein complexes. Autophosphorylated. In response to nutrient limitation, probably phosphorylated and activated by AMPK, leading to activate autophagy. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. APG1/unc-51/ULK1 subfamily. Extended N-terminus.