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Evaluation of Substrate Ubiquitylation by E3 Ubiquitin-ligase in Mammalian Cell Lysates
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Evaluation of Substrate Ubiquitylation by E3 Ubiquitin-ligase in Mammalian Cell Lysates

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Non-proteolytic ubiquitylation counteracts the APC/C-inhibitory function of XErp1

Eva Hörmanseder1, Thomas Tischer, Simone Heubes

  • 1Department of Molecular Genetics, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany.

EMBO Reports
|March 15, 2011
PubMed

Insights

A study on Xenopus oocytes reveals that increased UbcX enzyme activity overrides meiotic arrest by ubiquitylating XErp1, an anaphase-promoting complex/cyclosome (APC/C) inhibitor, leading to its dissociation from APC/C.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Developmental Biology

Background:

  • Mature Xenopus oocytes are arrested in meiosis via XErp1/Emi2, an inhibitor of the anaphase-promoting complex/cyclosome (APC/C).
  • Fertilization triggers XErp1 degradation, activating APC/C and initiating meiotic exit.

Purpose of the Study:

  • To investigate the role of the ubiquitin-conjugating enzyme UbcX in regulating meiotic arrest in Xenopus oocytes.
  • To elucidate the mechanism by which UbcX influences XErp1 stability and APC/C activity.

Main Methods:

  • Assessing the effect of increased UbcX activity on meiotic arrest.
  • Analyzing XErp1 stability and ubiquitylation status.
  • Investigating the interaction between UbcX, XErp1, and APC/C.

Main Results:

  • A modest increase in UbcX activity overrides meiotic arrest in an APC/C-dependent manner.
  • XErp1 remains stable under conditions of increased UbcX activity.
  • UbcX induces XErp1 ubiquitylation, causing its dissociation from APC/C.

Conclusions:

  • Ubiquitylation of XErp1 by UbcX regulates its inhibitory activity on APC/C.
  • This mechanism provides new insights into the control of meiotic progression and cell cycle regulation.

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