Serine/threonine protein kinase involved in the cytoplasm to vacuole transport (Cvt) and found to be essential in autophagy, where it is required for the formation of autophagosomes. Involved in the clearance of protein aggregates which cannot be efficiently cleared by the proteasome. Required for selective autophagic degradation of the nucleus (nucleophagy) as well as for mitophagy which contributes to regulate mitochondrial quantity and quality by eliminating the mitochondria to a basal level to fulfill cellular energy requirements and preventing excess ROS production (PubMed:18818209, PubMed:21576396, PubMed:22768199, PubMed:23230142). Also involved in endoplasmic reticulum-specific autophagic process, in selective removal of ER-associated degradation (ERAD) substrates (PubMed:21228276). Plays a key role in ATG9 and ATG23 cycling through the pre-autophagosomal structure and is necessary to promote ATG18 binding to ATG9 through phosphorylation of ATG9 (PubMed:14723849, PubMed:20855505, PubMed:24905091, PubMed:24440502). Catalyzes phosphorylation of ATG4, decreasing the interaction between ATG4 and ATG8 and impairing deconjugation of PE-conjugated forms of ATG8 (PubMed:28821724). Finally, ATG1 is also required for the maintenance of cell viability under starvation and for glycogen storage during stationary phase. Plays a role in genome stability through suppression of abnormal mitosis under starvation, and in regulation of filamentous growth. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Activated by hypophosphorylated form of ATG13 (present in nitrogen starvation conditions). Also activated by autophopsphorylation of Thr-226 and inhibited by phosphorylation of Ser-34. Homodimer. Dimerization requires the presence of ATG13. Forms a ternary complex with ATG13 and ATG17. Interacts also with ATG11. Formes punctate structures in starvation conditions only when ATG13 and ATG17 were both present. Localizes to both the isolation membrane (IM) and the vacuole-isolation membrane contact site (VICS) during IM expansion. The IM is a membrane sac generated from the pre-autophagosomal structure that ultimately expands to become a mature autophagosome. The LIR motif is required for the interaction with ATG8 and for the association of ATG1 with autophagosomes. Autophosphorylated at Thr-226 and Ser-390. The phosphorylation state may play a role in the induction of protein degradation upon starvation. Phosphorylation at Thr-226 within the activation loop is required for protein kinase activity whereas phosphorylation at Ser-34 leads to inhibition of kinase activity. Phosphorylation of Ser-508 and Ser-515 by PKA is required to induce autophagy but not for kinase activity. Present with 1070 molecules/cell in log phase SD medium. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. APG1/unc-51/ULK1 subfamily.