Emi1 regulates the anaphase-promoting complex by a different mechanism than Mad2 proteins

  1. Julie D.R. Reimann,
  2. Bryan E. Gardner,
  3. Florence Margottin-Goguet, and
  4. Peter K. Jackson1
  1. Departments of Pathology, Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305-5324, USA

Abstract

The anaphase-promoting complex/cyclosome (APC) ubiquitin ligase is activated by Cdc20 and Cdh1 and inhibited by Mad2 and the spindle assembly checkpoint complex, Mad2B, and the early mitotic inhibitor Emi1. Mad2 inhibits APCCdc20, whereas Mad2B preferentially inhibits APCCdh1. We have examined the mechanism of APC inhibition by Emi1 and find that unlike Mad2 proteins, Emi1 binds and inhibits both APCCdh1 and APCCdc20. Also unlike Mad2, Emi1 stabilizes cyclin A in the embryo and requires zinc for its APC inhibitory activity. We find that Emi1 binds the substrate-binding region of Cdc20 and prevents substrate binding to the APC, illustrating a novel mechanism of APC inhibition.

Keywords

Footnotes

  • ↵1 Corresponding author.

  • E-MAIL pjackson{at}cmgm.stanford.edu; FAX (650) 725-6902.

  • Article and publication are at http://www.genesdev.org/cgi/doi/10.1101/gad.945701.

    • Received September 18, 2001.
    • Accepted October 29, 2001.
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  1. doi: 10.1101/gad.945701 Genes & Dev. 15: 3278-3285 Cold Spring Harbor Laboratory Press

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