an protein required for autophagosome formation. Interacts with ATG13. Associates with a complex composed of ATG13, ULK1 and RB1CC1. Under starvation conditions it localizes to phagophores, which are preautophagosomal structures. Stabilizes the expression of Atg13 in the cell. Belongs to the ATG101 family. Note: This description may include information from UniProtKB.