Levels of the ubiquitin ligase substrate adaptor MEL-26 are inversely correlated with MEI-1/katanin microtubule-severing activity during both meiosis and mitosis

Jacque Lynne F A Johnson, Chenggang Lu, Eko Raharjo, Karen McNally, Francis J. McNally, Paul E. Mains

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

The MEI-1/MEI-2 microtubule-severing complex, katanin, is required for oocyte meiotic spindle formation and function in C. elegans, but the microtubule-severing activity must be quickly downregulated so that it does not interfere with formation of the first mitotic spindle. Post-meiotic MEI-1 inactivation is accomplished by two parallel protein degradation pathways, one of which requires MEL-26, the substrate-specific adaptor that recruits MEI-1 to a CUL-3 based ubiquitin ligase. Here we address the question of how MEL-26 mediated MEI-1 degradation is triggered only after the completion of MEI-1's meiotic function. We find that MEL-26 is present only at low levels until the completion of meiosis, after which protein levels increase substantially, likely increasing the post-meiotic degradation of MEI-1. During meiosis, MEL-26 levels are kept low by the action of another type of ubiquitin ligase, which contains CUL-2. However, we find that the low levels of meiotic MEL-26 have a subtle function, acting to moderate MEI-1 activity during meiosis. We also show that MEI-1 is the only essential target for MEL-26, and possibly for the E3 ubiquitin ligase CUL-3, but the upstream ubiquitin ligase activating enzyme RFL-1 has additional essential targets.

Original languageEnglish (US)
Pages (from-to)349-357
Number of pages9
JournalDevelopmental Biology
Volume330
Issue number2
DOIs
StatePublished - Jun 15 2009

Keywords

  • C. elegans
  • Meiosis
  • Protein degradation
  • Spindle

ASJC Scopus subject areas

  • Developmental Biology
  • Cell Biology
  • Molecular Biology

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