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Use of Time-Lapse Microscopy and Stage-Specific Nuclear Depletion of Proteins to Study Meiosis in S. cerevisiae
07:48

Use of Time-Lapse Microscopy and Stage-Specific Nuclear Depletion of Proteins to Study Meiosis in S. cerevisiae

Published on: October 11, 2022

Phosphorylation of Ime2 regulates meiotic progression in Saccharomyces cerevisiae

Karen Schindler1, Edward Winter

  • 1Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.

The Journal of Biological Chemistry
|May 11, 2006
PubMed

Insights

Ime2p, a meiosis kinase in yeast, is activated by phosphorylation and autophosphorylation. Its C-terminal phosphorylation influences exit from meiosis I, revealing a regulatory pathway for meiotic progression.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Genetics

Background:

  • Ime2p is a meiosis-specific protein kinase in Saccharomyces cerevisiae.
  • Its function is related to Cdc28p cyclin-dependent kinase (CDK), but regulatory cyclin partners are unknown.
  • Ime2p shares sequence similarity with CDKs and mitogen-activated protein kinases (MAPKs).

Purpose of the Study:

  • To investigate the phosphorylation status and regulation of Ime2p during meiosis.
  • To determine the role of Ime2p phosphorylation in meiotic progression and sporulation.
  • To elucidate the functional significance of Ime2p C-terminal phosphorylation sites.

Main Methods:

  • Purification of Ime2p from meiotic yeast cells.
  • In vitro kinase assays to assess autophosphorylation.
  • Analysis of Ime2p phosphorylation sites using mass spectrometry.
  • Genetic interaction studies with components of the FEAR network.

Main Results:

  • Purified Ime2p is phosphorylated on activation loop (Thr242, Tyr244) and C-terminus (Ser520, Ser625).
  • Ime2p autophosphorylates on threonine in the activation loop in vitro, crucial for hyperphosphorylation.
  • C-terminal phosphorylation is not essential for sporulation but interacts genetically with the FEAR network.

Conclusions:

  • Autophosphorylation is essential for Ime2p activation and subsequent hyperphosphorylation.
  • Ime2p plays a role in controlling exit from meiosis I, mediated by C-terminal phosphorylation.
  • A phospho-modification pathway regulates Ime2p activity throughout meiotic development.

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