RT Journal Article
SR Electronic
T1 Efficient APC/C substrate degradation in cells undergoing mitotic exit depends on K11 ubiquitin linkages
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 016139
DO 10.1101/016139
A1 Mingwei Min
A1 Tycho Mevissen
A1 Maria De Luca
A1 David Komander
A1 Catherine Lindon
YR 2015
UL http://biorxiv.org/content/early/2015/03/06/016139.abstract
AB The ubiquitin proteasome system (UPS) directs programmed destruction of key cellular regulators via post-translational modification of its targets with polyubiquitin chains. These commonly contain Lysine 48 (K48)-directed ubiquitin linkages, but chains containing atypical Lysine 11 (K11) linkages also target substrates to the proteasome, for example to regulate cell cycle progression. A single ubiquitin ligase, the Anaphase Promoting Complex/Cyclosome (APC/C), controls mitotic exit. In higher eukaryotes, the APC/C works with the E2 enzyme UBE2S to assemble K11 linkages in cells released from mitotic arrest, and these are proposed to constitute an improved proteolytic signal during exit from mitosis. We have tested this idea by correlating quantitative measures of in vivo K11-specific ubiquitination of individual substrates, including Aurora kinases, with their degradation kinetics tracked at the single cell level. We report that all anaphase substrates tested by this methodology are stabilized by depletion of K11 linkages via UBE2S knockdown, even if the same substrates are significantly modified with K48-linked polyubiquitin. Specific examination of substrates depending on the APC/C coactivator Cdh1 for their degradation revealed Cdh1-dependent enrichment of K11 chains on these substrates, while other ubiquitin linkages on the same substrates added during mitotic exit were Cdh1-independent. Therefore we show that K11 linkages provide the APC/C with a means to regulate the rate of substrate degradation in a co-activator-specified manner.APC/CAnaphase Promoting Complex/CyclosomeDUBdeubiquitinaseSACspindle assembly checkpointUPSubiquitin-proteasome systemZMZM447439