Deubiquitinating enzymes (DUBs) are proteases that posses the ability to cleave ubiquitin chains or the isopeptide bond that conjugates ubiquitin with a substrate. Human cells have approximately 100 DUBs that play important roles in regulating various cellular events. OTUB1 is a member of the ovarian tumor domain family. It is recognized as a K48 ubiquitin chain-specific DUB and can inhibit E2 enzymes, especially Ubc13 (also known as Ube2N), which is known to synthesize K63-linked ubiquitin chains. OTUB1 may also deubiquitinate TRAF3 and -6. This would negatively regulate virus-triggered type I IFN induction.
