Anti-ATG4B antibodies are used in the immunodetection of the protein autophagy related 4B cysteine peptidase. In humans, the canonical protein has a reported length of 393 amino acid residues and a mass of 44.3 kDa. Its subcellular localization is in the cytoplasmic vesicles, mitochondria, ER, and cytoplasm. Up to 5 different isoforms have been reported for this protein. It is notably expressed in many tissues, such as the appendix and colon. A member of the Peptidase C54 protein family, ATG4B is reported to be a cysteine protease that plays a key role in autophagy by mediating both proteolytic activation and delipidation of ATG8 family proteins. Synonyms for this target antigen include AUTL1, HsAPG4B, cysteine protease ATG4B, APG4 autophagy 4 homolog B, ATG4 autophagy related 4 homolog B, and APG4B. ATG4B gene orthologs have been reported in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species. Over 100 citations in the literature describe the use of ATG4B antibodies in research. Western Blot is a widely used application for these antibodies. ELISA and Immunohistochemistry are also common applications.