5lgg

From Proteopedia

The N-terminal WD40 domain of Apc1 (Anaphase promoting complex subunit 1)

PDB ID 5lgg

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Structural highlights

5lgg is a 1 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.15Å
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

APC1_HUMAN Component of the anaphase promoting complex/cyclosome (APC/C), a cell cycle-regulated E3 ubiquitin ligase that controls progression through mitosis and the G1 phase of the cell cycle. The APC/C complex acts by mediating ubiquitination and subsequent degradation of target proteins: it mainly mediates the formation of 'Lys-11'-linked polyubiquitin chains and, to a lower extent, the formation of 'Lys-48'- and 'Lys-63'-linked polyubiquitin chains.^[1]

Publication Abstract from PubMed

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-A 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.

WD40 domain of Apc1 is critical for the coactivator-induced allosteric transition that stimulates APC/C catalytic activity.,Li Q, Chang L, Aibara S, Yang J, Zhang Z, Barford D Proc Natl Acad Sci U S A. 2016 Sep 20;113(38):10547-52. doi:, 10.1073/pnas.1607147113. Epub 2016 Sep 6. PMID:27601667^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Jin L, Williamson A, Banerjee S, Philipp I, Rape M. Mechanism of ubiquitin-chain formation by the human anaphase-promoting complex. Cell. 2008 May 16;133(4):653-65. doi: 10.1016/j.cell.2008.04.012. PMID:18485873 doi:http://dx.doi.org/10.1016/j.cell.2008.04.012
↑ Li Q, Chang L, Aibara S, Yang J, Zhang Z, Barford D. WD40 domain of Apc1 is critical for the coactivator-induced allosteric transition that stimulates APC/C catalytic activity. Proc Natl Acad Sci U S A. 2016 Sep 20;113(38):10547-52. doi:, 10.1073/pnas.1607147113. Epub 2016 Sep 6. PMID:27601667 doi:http://dx.doi.org/10.1073/pnas.1607147113