An approximately 350-residue amino acid polypeptide, designated protein FAM105A (also known as OTULINL), has been identified in a range of vertebrates. It shares a high degree of similarity with protein FAM105B (also known as OTULIN), an ubiquitin thioesterase. Despite their similarity, FAM105A lacks the conserved active site at position 139 which is replaced by an Asp residue, and does not show deubiquitinase activity [].
