OTU (ovarian tumor) domain of deubiquitinating enzyme OTU4 from plants and similar proteins
Deubiquitinating enzyme OTU4, also called OTU domain-containing protein 4, is a deubiquitinase (DUB) or ubiquitin thiolesterase (EC 3.4.19.12) that catalyzes the thiol-dependent hydrolysis of ester, thioester, amide, peptide and isopeptide bonds formed by the C-terminal Gly of ubiquitin, a small regulatory protein that can be conjugated to a large range of target proteins. Protein ubiquitination is a post-translational modification of mostly Lys residues that regulates many cellular processes, including protein degradation, intracellular trafficking, cell signaling, autophagy, transcription, translation, and the DNA damage response. OTU4 may play an important regulatory role at the level of protein turnover by preventing degradation. OTU4 belongs to the OTU family of cysteine proteases that use a conserved cysteine, histidine, and an aspartate, as the catalytic triad.