OTU (ovarian tumor) domain of Arabidopsis thaliana deubiquitinating enzyme OTU7 and similar proteins
Arabidopsis thaliana deubiquitinating enzyme OTU7, also called OTU domain-containing protein 7, is a deubiquitinase (DUB)/ubiquitin thioesterase (EC 3.4.19.12) that shows a preference for 'Lys-63' over 'Lys-48' over 'Met-1'-linked ubiquitin (UB) tetramers as substrates. DUBs catalyze 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. These DUBs may play important regulatory roles at the level of protein turnover by preventing degradation. OTU7 belongs to the OTU family of cysteine proteases that use a conserved cysteine, histidine, and an aspartate, as the catalytic triad.