Component of the unc-51/atg-13 complex required for autophagosome formation (PubMed:19377305, PubMed:26687600). Required for the degradation of germ cell specific P-granule components such as sepa-1 by autophagy in somatic cells (PubMed:19377305). This ensures exclusive localization of the P-granules in germ cells (PubMed:19377305). May function downstream of the let-363 (Tor) signaling pathway to mediate sepa-1 degradation (PubMed:19377305). Plays a role in survival during limited food availability (PubMed:19377305). Interacts with unc-51 (via C-terminus) (PubMed:19377305). Interacts with lgg-1; the interaction is direct (PubMed:26687600). Under starvation conditions, is localized to punctate structures primarily representing the isolation membrane that sequesters a portion of the cytoplasm resulting in the formation of an autophagosome. Recruited to preautophagosomes by lgg-1 (PubMed:26687600). Expressed from the 8-cell stage and subsequently throughout embryogenesis. After hatching, highly expressed in neurons including nerve ring cells, neurons in the tail and DD/VD motor neurons in the ventral nerve cord. Also expressed in body wall muscle and pharyngeal muscle. Belongs to the ATG13 family. Metazoan subfamily.