OTU (ovarian tumor) domain of OTU domain-containing protein 5 and similar proteins
OTU domain-containing protein 5 (OTUD5), also called deubiquitinating enzyme A (DUBA), is a phosphorylation-dependent deubiquitinase (DUB)/ubiquitin thioesterase (EC 3.4.19.12) that can hydrolyze 'Lys-48'- and 'Lys-63'-linked polyubiquitin chains, and may function as negative regulator of the innate immune system. It limits type I interferon production in macrophages and suppresses interleukin-17A production in T cells. OTUD5 also functions in an apoptotic signaling cascade by mediating the sequential activation of PDCD5 (programmed cell death 5) and p53 in response to genotoxic stress. In Drosophila, OTUD5/DUBA is essential for spermatogenesis. This subfamily also includes Arabidopsis thaliana OTU domain-containing protein 6, also called deubiquitinating enzyme OTU6 or otubain-like deubiquitinase 1 (OTLD1), which binds chromatin and has enzymatic histone deubiquitinase activity specific for the H2B histone. This subfamily belongs to the OTU family of cysteine proteases that use a conserved cysteine, histidine, and an aspartate, as the catalytic triad. It also includes plant OTU6.