Structural insights into the activation of ubiquitin-specific protease 46 by WDR48 and WDR20
作者单位：State Key Laboratory of Molecular BiologyNational Center for Protein Science Shanghai Shanghai Science Research Center CAS Center for Excellence in Molecular Cell Science Shanghai Institute of Biochemistry and Cell Biology University of Chinese Academy of Sciences Chinese Academy of Sciences
会议名称：《中国生物化学与分子生物学会2019年全国学术会议暨学会成立四十周年》
会议日期：2019年
学科分类：0710[理学-生物学] 071010[理学-生物化学与分子生物学] 081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术]
关 键 词：Ubiquitination deubiquitinases ubiquitin-specific proteases USP46 WD40-repeat protein allosteric regulation
摘 要：Ubiquitination is an important and reversible post-translational modification that regulates the stability, localization and function of proteins in many cellular processes. Deubiquitinases are responsible for the removal of ubiquitin chains from proteins, and ubiquitin-specific proteases(USPs) are the largest family of deubiquitinases, some of which are regulated by WD40-repeat proteins. The deubiquitinating activity of USP46 can be activated by WDR48 and WDR20;however, the molecular mechanism remains elusive. We determined the crystal structure of the USP46-WDR48-WDR20 complex at 3.1 ? resolution and validated the functional roles of key residues involved in the assembly of the complex with both in vitro and in vivo functional assays. The structural and functional data demonstrate that the binding of WDR48 and WDR20 can activate the activity of USP46 independently and synergistically and plays an indispensible role in USP46-mediated deubiquitination of PHLPP1 in the Akt signaling pathway. Detailed comparison of all available USP46 and USP12 structures reveals that the WDR48 binding not only stabilizes the Fingers subdomain but also increases conformational flexibility of several structural elements surrounding the catalytic center;and the combined effects render a moderate activation of the USPs. The further binding of WDR20 largely restores the WDR48-binding induced conformational changes and stabilizes the conformations of those structural elements surrounding the catalytic center, and thus potentiates the activity of the USPs. These results provide new insights into the molecular mechanism of the activation of USPs by WD40-repeat proteins.