6s96
Crystal structure of the catalytic domain of UBE2S C118A.
Structural highlights
FunctionUBE2S_HUMAN Accepts ubiquitin from the E1 complex and catalyzes its covalent attachment to other proteins. Catalyzes 'Lys-11'-linked polyubiquitination. Acts as an essential factor of the anaphase promoting complex/cyclosome (APC/C), a cell cycle-regulated ubiquitin ligase that controls progression through mitosis. Acts by specifically elongating 'Lys-11'-linked polyubiquitin chains initiated by the E2 enzyme UBE2C/UBCH10 on APC/C substrates, enhancing the degradation of APC/C substrates by the proteasome and promoting mitotic exit. Also acts by elongating ubiquitin chains initiated by the E2 enzyme UBE2D1/UBCH5 in vitro; it is however unclear whether UBE2D1/UBCH5 acts as a E2 enzyme for the APC/C in vivo. Also involved in ubiquitination and subsequent degradation of VHL, resulting in an accumulation of HIF1A. In vitro able to promote polyubiquitination using all 7 ubiquitin Lys residues, except 'Lys-48'-linked polyubiquitination.[1] [2] [3] [4] [5] Publication Abstract from PubMedAt the heart of protein ubiquitination cascades, ubiquitin-conjugating enzymes (E2s) form reactive ubiquitin-thioester intermediates to enable efficient transfer of ubiquitin to cellular substrates. The precise regulation of E2s is thus crucial for cellular homeostasis, and their deregulation is frequently associated with tumorigenesis. In addition to driving substrate ubiquitination together with ubiquitin ligases (E3s), many E2s can also autoubiquitinate, thereby promoting their own proteasomal turnover. To investigate the mechanisms that balance these disparate activities, we dissected the regulatory dynamics of UBE2S, a human APC/C-associated E2 that ensures the faithful ubiquitination of cell cycle regulators during mitosis. We uncovered a dimeric state of UBE2S that confers autoinhibition by blocking a catalytically critical ubiquitin binding site. Dimerization is stimulated by the lysine-rich carboxyl-terminal extension of UBE2S that is also required for the recruitment of this E2 to the APC/C and is autoubiquitinated as substrate abundance becomes limiting. Consistent with this mechanism, we found that dimerization-deficient UBE2S turned over more rapidly in cells and did not promote mitotic slippage during prolonged drug-induced mitotic arrest. We propose that dimerization attenuates the autoubiquitination-induced turnover of UBE2S when the APC/C is not fully active. More broadly, our data illustrate how the use of mutually exclusive macromolecular interfaces enables modulation of both the activities and the abundance of E2s in cells to facilitate precise ubiquitin signaling. Dimerization regulates the human APC/C-associated ubiquitin-conjugating enzyme UBE2S.,Liess AKL, Kucerova A, Schweimer K, Schlesinger D, Dybkov O, Urlaub H, Mansfeld J, Lorenz S Sci Signal. 2020 Oct 20;13(654). pii: 13/654/eaba8208. doi:, 10.1126/scisignal.aba8208. PMID:33082289[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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