Journal
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Volume 113, Issue 38, Pages 10547-10552Publisher
NATL ACAD SCIENCES
DOI: 10.1073/pnas.1607147113
Keywords
APC/C; ubiquitination; cell cycle; UbcH10; Ube2S
Categories
Funding
- Cancer Research-UK Programme [C576/A14109]
- Medcal Research Council Laboratory of Molecular Biology [MRC_UP_1201/6]
- Institute of Cancer Research Studentship
- Cancer Research UK [14109] Funding Source: researchfish
- Medical Research Council [MC_U105178939, MC_UP_1201/6] Funding Source: researchfish
- MRC [MC_UP_1201/6, MC_U105178939] Funding Source: UKRI
Ask authors/readers for more resources
The anaphase-promoting complex/cyclosome (APC/C) is a large multimeric cullin-RING E3 ubiquitin ligase that orchestrates cell-cycle progression by targeting cell-cycle regulatory proteins for destruction via the ubiquitin proteasome system. The APC/C assembly comprises two scaffolding subcomplexes: the platform and the TPR lobe that together coordinate the juxtaposition of the catalytic and substrate-recognition modules. The platform comprises APC/C subunits Apc1, Apc4, Apc5, and Apc15. Although the role of Apc1 as an APC/C scaffolding subunit has been characterized, its specific functions in contributing toward APC/C catalytic activity are not fully understood. Here, we report the crystal structure of the N-terminal domain of human Apc1 (Apc1N) determined at 2.2-angstrom resolution and provide an atomic-resolution description of the architecture of its WD40 (WD40 repeat) domain (Apc1(WD40)). To understand how Apc1(WD40) contributes to APC/C activity, a mutant form of the APC/C with Apc1(WD40) deleted was generated and evaluated biochemically and structurally. We found that the deletion of Apc1(WD40) abolished the UbcH10-dependent ubiquitination of APC/C substrates without impairing the Ube2S-dependent ubiquitin chain elongation activity. A cryo-EM structure of an APC/C-Cdh1 complex with Apc1(WD40) deleted showed that the mutant APC/C is locked into an inactive conformation in which the UbcH10-binding site of the catalytic module is inaccessible. Additionally, an EM density for Apc15 is not visible. Our data show that Apc1(WD40) is required to mediate the coactivator-induced conformational change of the APC/C that is responsible for stimulating APC/C catalytic activity by promoting UbcH10 binding. In contrast, Ube2S activity toward APC/C substrates is not dependent on the initiation-competent conformation of the APC/C.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available