Protein kinase important for axonal elongation and axonal guidance (PubMed:7958904, PubMed:15539493). Functions in the CAN axons to direct both anterior and posterior migrations (PubMed:15539493). Phosphorylates both unc-14 and vab-8 (PubMed:15539493). Component of the unc-51/atg-13 complex that is probably recruited by lgg-1 to preautophagosomes and is required for autophagosome formation (PubMed:12958363, PubMed:17890369, PubMed:19377305, PubMed:26687600). Interaction with autophagy related proteins such as atg-13 links it to the autophagy machinery to in turn promote P-granule degradation in somatic cells (PubMed:19377305). Plays a role in mitophagy during limited food availability (PubMed:30133321). Regulates cell size (PubMed:17890369). Plays a role in male tail ray pattern formation (PubMed:17890369). May be required for normal dauer morphogenesis (PubMed:12958363). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Interacts with unc-14 and vab-8 (PubMed:15539493). Interacts (via C-terminus) with atg-13 (PubMed:19377305). Interacts (via the LIR motif) with lgg-1; the interaction is direct (PubMed:26687600). During embryonic development unc-51 is expressed extensively, particularly in the head region of late embryos. In the larval stages, expression appears to be restricted to neurons. The LIR motif (LC3-interacting region) is required for its interaction with lgg-1. Worms exhibit various abnormalities in axonal elongation and axonal structures (PubMed:7958904). RNAi-mediated knockdown causes abnormalities in constitutive dauer formation in daf-2 e1370 mutant including a lack of autophagosome formation (PubMed:12958363). Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. APG1/unc-51/ULK1 subfamily.