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  • Molecular mechanisms of APC/C release from spindle assembly checkpoint inhibition by APC/C SUMOylation.

Molecular mechanisms of APC/C release from spindle assembly checkpoint inhibition by APC/C SUMOylation.

Cell reports (2021-04-01)
Stanislau Yatskevich, Jessie S Kroonen, Claudio Alfieri, Thomas Tischer, Anna C Howes, Linda Clijsters, Jing Yang, Ziguo Zhang, Kaige Yan, Alfred C O Vertegaal, David Barford
ABSTRACT

The anaphase-promoting complex/cyclosome (APC/C) is an E3 ubiquitin ligase that controls cell cycle transitions. Its regulation by the spindle assembly checkpoint (SAC) is coordinated with the attachment of sister chromatids to the mitotic spindle. APC/C SUMOylation on APC4 ensures timely anaphase onset and chromosome segregation. To understand the structural and functional consequences of APC/C SUMOylation, we reconstituted SUMOylated APC/C for electron cryo-microscopy and biochemical analyses. SUMOylation of the APC/C causes a substantial rearrangement of the WHB domain of APC/C's cullin subunit (APC2WHB). Although APC/CCdc20 SUMOylation results in a modest impact on normal APC/CCdc20 activity, repositioning APC2WHB reduces the affinity of APC/CCdc20 for the mitotic checkpoint complex (MCC), the effector of the SAC. This attenuates MCC-mediated suppression of APC/CCdc20 activity, allowing for more efficient ubiquitination of APC/CCdc20 substrates in the presence of the MCC. Thus, SUMOylation stimulates the reactivation of APC/CCdc20 when the SAC is silenced, contributing to timely anaphase onset.

MATERIALS
Product Number
Brand
Product Description

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Biotin, ≥99% (HPLC), lyophilized powder
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Anti-phospho-Histone H3 (Ser10) Antibody, Mitosis Marker, Upstate®, from rabbit
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Phenylmethanesulfonyl fluoride, ≥99.0% (T)
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(+)-S-Trityl-L-cysteine, 97%
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d-Desthiobiotin, ≥98% (TLC)
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Thymidine, ≥99%
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Spermine, Tetrahydrochloride