Membrane-binding domains in autophagy.

Highlights • Autophagy involves complicated membrane dynamics that are regulated by Atg proteins. • Most Atg proteins lack transmembrane helices and bind membranes using membrane-binding domains and motifs. • Atg1 complex recruits Atg9 vesicles as an initial membrane source through protein-protein interaction. • Autophagy-specific phosphatidylinositol 3-kinase complex binds membranes using amphipathic helices and an aromatic loop. • Atg2-Atg18 and Atg20-Atg24 complexes target to membranes via binding to phosphatidylinositol 3-phosphate. • Atg conjugation system binds membranes via Atg3 and Atg5, and covalently conjugates Atg8 to phosphatidylethanolamine. Abstract Autophagy is an intracellular degradation system conserved among eukaryotes that mediates the degradation of various biomolecules and organelles. During autophagy, a double membrane-bound organelle termed an autophagosome is synthesized de novo and delivers targets from the cytoplasm to the lysosomes for degradation. Autophagosome formation involves complex and dynamic membrane rearrangements, which are regulated by dozens of autophagy-related (Atg) proteins. In this review, we summarize our current knowledge of membrane-binding domains and motifs in Atg proteins and discuss their roles in autophagy. [ABSTRACT FROM AUTHOR]