E1-like activating enzyme involved in the 2 ubiquitin-like systems required for autophagy (PubMed:12626495). Activates atg12 for its conjugation with atg5 and atg8 for its conjugation with phosphatidylethanolamine. Both systems are needed for the atg8 association to autophagosomes membranes (By similarity). Required for normal survival when exposed to pathogenic bacteria S.typhimurium by promoting autophagic degradation of intracellular S.typhimurium (PubMed:19667176). Homodimer. Interacts with atg8 through a thioester bond between Cys-563 and the C-terminal 'Gly-120' of atg8 and with ATG12 through a thioester bond between Cys-563 and the C-terminal 'Gly-124' of atg12 (By similarity). The GxGxxG motif is important for the function, possibly through binding with ATP. Impaired survival when exposed to pathogenic bacteria S.typhimurium associated with the accumulation of S.typhimuriumin in large vacuoles which fail to undergo autophagy. Belongs to the ATG7 family.