Autophagy is a process of intracellular bulk degradation in which cytoplasmic components including organelles are sequestered within double-membrane vesicles that deliver the contents to the lysosome/vacuole for degradation. Autophagy has two ubiquitin-like conjugation systems, the Atg12 and LC3-II systems. In the Atg12 conjugation system, Atg10 functions as E2-like enzyme, plays a role to form conjugates of Atg12 and Atg5. Atg12-Atg5 complex interacts with Atg16L and forms 800 kDa complex that elongate autophagic isolation membrane.