E2-like enzyme required for the cytoplasm to vacuole transport (Cvt), autophagy and nucleophagy. Acts as an E2-like enzyme that catalyzes the conjugation of ATG12 to ATG5. ATG12 conjugation to ATG5 is required for proper localization of ATG8 to the preautophagosomal structure (PAS). Likely serves as an ATG5-recognition molecule (By similarity). Forms homooligomers. Expression is decreased upon fluphenazine treatment. Belongs to the ATG10 family.