Atg8 is a ubiquitin-like protein that is conjugated to phosphatidylethanolamine on autophagosome membranes by Atg7 (an E1-like protein), Atg3 (an E2-like protein), and Atg12-Atg5 (an E3-like enzyme). Atg8 is proposed to have multiple functions during autophagy, including membrane elongation, cargo recognition, edge closure, autophagosomal movement, and autophagosomal tethering to lysosomes. (Adapted from PMID:18704115 and PMID:31901645.)