ATG4B, APG4B, AUTL1, KIAA0943, Cysteine protease ATG4B, AUT-like 1 cysteine endopeptidase, Autophagin-1, Autophagy-related cysteine endopeptidase 1, Autophagy-related protein 4 homolog B

Macroautophagy is the major inducible pathway for the general turnover of cytoplasmic constituents in eukaryotic cells, it is also responsible for the degradation of active cytoplasmic enzymes and organelles during nutrient starvation. Macroautophagy involves the formation of double-membrane bound autophagosomes which enclose the cytoplasmic constituent targeted for degradation in a membrane bound structure, which then fuse with the lysosome (or vacuole) releasing a single-membrane bound autophagic bodies which are then degraded within the lysosome (or vacuole). APG4, a cysteine protease required for autophagy, cleaves the C-terminal part of MAP1LC3 to form the activated molecule LC3-I. LC3-I is subsequently conjugated with phosphatidylethanolamine at the C-terminal glycine to form LC3-II, a marker for autophagy via its capacity to bind to autophagosomes.