Inhibition of the anaphase-promoting complex by the Xnf7 ubiquitin ligase.

Published

Journal Article

Degradation of specific protein substrates by the anaphase-promoting complex/cyclosome (APC) is critical for mitotic exit. We have identified the protein Xenopus nuclear factor 7 (Xnf7) as a novel APC inhibitor able to regulate the timing of exit from mitosis. Immunodepletion of Xnf7 from Xenopus laevis egg extracts accelerated the degradation of APC substrates cyclin B1, cyclin B2, and securin upon release from cytostatic factor arrest, whereas excess Xnf7 inhibited APC activity. Interestingly, Xnf7 exhibited intrinsic ubiquitin ligase activity, and this activity was required for APC inhibition. Unlike other reported APC inhibitors, Xnf7 did not associate with Cdc20, but rather bound directly to core subunits of the APC. Furthermore, Xnf7 was required for spindle assembly checkpoint function in egg extracts. These data suggest that Xnf7 is an APC inhibitor able to link spindle status to the APC through direct association with APC core components.

Full Text

Duke Authors

Cited Authors

  • Casaletto, JB; Nutt, LK; Wu, Q; Moore, JD; Etkin, LD; Jackson, PK; Hunt, T; Kornbluth, S

Published Date

  • April 2005

Published In

Volume / Issue

  • 169 / 1

Start / End Page

  • 61 - 71

PubMed ID

  • 15824132

Pubmed Central ID

  • 15824132

Electronic International Standard Serial Number (EISSN)

  • 1540-8140

International Standard Serial Number (ISSN)

  • 1540-8140

Digital Object Identifier (DOI)

  • 10.1083/jcb.200411056

Language

  • eng