Background：

Hydrolase that removes conjugated ubiquitin from target proteins and regulates various pathways such as the TGF-beta receptor signaling， NF-kappa-B and RNF41/NRDP1-PRKN pathways. Acts as a key regulator of TGF-beta receptor signaling pathway， but the precise mechanism is still unclear: according to a report， acts by promoting deubiquitination of monoubiquitinated R-SMADs (SMAD1， SMAD2 and/or SMAD3)， thereby alleviating inhibition of R-SMADs and promoting activation of TGF-beta target genes. According to another reports， regulates the TGF-beta receptor signaling pathway by mediating deubiquitination and stabilization of TGFBR1， leading to an enhanced TGF-beta signal. Able to mediate deubiquitination of monoubiquitinated substrates as well as ’Lys-48’-linked polyubiquitin chains， protecting them against proteasomal degradation. May also regulate gene expression and/or DNA repair through the deubiquitination of histone H2B. Acts as an inhibitor of mitophagy by counteracting the action of park