Molecular architecture and mechanism of the anaphase-promoting complex

Nature. 2014 Sep 18;513(7518):388-393. doi: 10.1038/nature13543. Epub 2014 Jul 20.

Abstract

The ubiquitination of cell cycle regulatory proteins by the anaphase-promoting complex/cyclosome (APC/C) controls sister chromatid segregation, cytokinesis and the establishment of the G1 phase of the cell cycle. The APC/C is an unusually large multimeric cullin-RING ligase. Its activity is strictly dependent on regulatory coactivator subunits that promote APC/C-substrate interactions and stimulate its catalytic reaction. Because the structures of many APC/C subunits and their organization within the assembly are unknown, the molecular basis for these processes is poorly understood. Here, from a cryo-electron microscopy reconstruction of a human APC/C-coactivator-substrate complex at 7.4 Å resolution, we have determined the complete secondary structural architecture of the complex. With this information we identified protein folds for structurally uncharacterized subunits, and the definitive location of all 20 APC/C subunits within the 1.2 MDa assembly. Comparison with apo APC/C shows that the coactivator promotes a profound allosteric transition involving displacement of the cullin-RING catalytic subunits relative to the degron-recognition module of coactivator and APC10. This transition is accompanied by increased flexibility of the cullin-RING subunits and enhanced affinity for UBCH10-ubiquitin, changes which may contribute to coactivator-mediated stimulation of APC/C E3 ligase activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Allosteric Regulation
  • Anaphase-Promoting Complex-Cyclosome / chemistry
  • Anaphase-Promoting Complex-Cyclosome / metabolism*
  • Anaphase-Promoting Complex-Cyclosome / ultrastructure*
  • Apc10 Subunit, Anaphase-Promoting Complex-Cyclosome / chemistry
  • Apc10 Subunit, Anaphase-Promoting Complex-Cyclosome / metabolism
  • Catalytic Domain
  • Cdh1 Proteins / chemistry
  • Cdh1 Proteins / metabolism
  • Cdh1 Proteins / ultrastructure
  • Cryoelectron Microscopy
  • Humans
  • Models, Molecular
  • Pliability
  • Protein Folding
  • Protein Structure, Secondary
  • Protein Subunits / chemistry
  • Protein Subunits / metabolism
  • Ubiquitin / metabolism
  • Ubiquitin-Conjugating Enzymes / metabolism
  • Ubiquitination

Substances

  • ANAPC10 protein, human
  • Apc10 Subunit, Anaphase-Promoting Complex-Cyclosome
  • Cdh1 Proteins
  • Protein Subunits
  • Ubiquitin
  • UBE2C protein, human
  • Ubiquitin-Conjugating Enzymes
  • Anaphase-Promoting Complex-Cyclosome