6tm5

From Proteopedia

Cryo-EM structure of the Anaphase-promoting complex/Cyclosome, in complex with the Nek2A substrate at 3.9 angstrom resolution

6tm5, resolution 3.90Å

Structural highlights

6tm5 is a 14 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:	Electron Microscopy, Resolution 3.9Å
Ligands:
Experimental data:	Check to display Experimental Data
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 (APC/C) is the key E3 ubiquitin ligase which directs mitotic progression and exit by catalysing the sequential ubiquitination of specific substrates. The activity of the APC/C in mitosis is restrained by the spindle assembly checkpoint (SAC), which coordinates chromosome segregation with the assembly of the mitotic spindle. The SAC effector is the mitotic checkpoint complex (MCC), which binds and inhibits the APC/C. It is incompletely understood how the APC/C switches substrate specificity in a cell cycle-specific manner. For instance, it is unclear how in prometaphase, when APC/C activity towards cyclin B and securin is repressed by the MCC, the kinase Nek2A is ubiquitinated. Here, we combine biochemical and structural analysis with functional studies in cells to show that Nek2A is a conformational-specific binder of the APC/C-MCC complex (APC/C(MCC) ) and that, in contrast to cyclin A, Nek2A can be ubiquitinated efficiently by the APC/C in conjunction with both the E2 enzymes UbcH10 and UbcH5. We propose that these special features of Nek2A allow its prometaphase-specific ubiquitination.

A unique binding mode of Nek2A to the APC/C allows its ubiquitination during prometaphase.,Alfieri C, Tischer T, Barford D EMBO Rep. 2020 Apr 19:e49831. doi: 10.15252/embr.201949831. PMID:32307883^[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
↑ Alfieri C, Tischer T, Barford D. A unique binding mode of Nek2A to the APC/C allows its ubiquitination during prometaphase. EMBO Rep. 2020 Apr 19:e49831. doi: 10.15252/embr.201949831. PMID:32307883 doi:http://dx.doi.org/10.15252/embr.201949831