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Combining Mitotic Cell Synchronization and High Resolution Confocal Microscopy to Study the Role of Multifunctional Cell Cycle Proteins During Mitosis
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MEK1 inactivates Myt1 to regulate Golgi membrane fragmentation and mitotic entry in mammalian cells

Julien Villeneuve1, Margherita Scarpa, Maria Ortega-Bellido

  • 1Cell and Developmental Biology Programme, Centre for Genomic Regulation, Barcelona, Spain.

The EMBO Journal
|December 18, 2012
PubMed

Insights

Mitogen-activated protein kinase kinase 1 (MEK1) inactivates Myt1 through phosphorylation, leading to Golgi complex fragmentation and mitotic entry. Myt1 is a key regulator connecting Golgi fragmentation to cell cycle progression.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • The Golgi complex undergoes significant fragmentation during mitosis.
  • Mitogen-activated protein kinase kinase 1 (MEK1) plays a role in Golgi fragmentation and mitotic entry.

Purpose of the Study:

  • To elucidate the role of Myt1 in MEK1-mediated Golgi fragmentation and mitotic entry.
  • To identify the mechanism by which MEK1 influences Golgi structure and cell cycle progression.

Main Methods:

  • Small interfering RNA (siRNA) mediated knockdown of Myt1 in HeLa cells.
  • Analysis of Golgi complex fragmentation in permeabilized and intact cells.
  • Investigation of Myt1 phosphorylation by MEK1 and its dependence on other kinases.

Main Results:

  • Myt1 knockdown enhanced Golgi complex fragmentation and alleviated MEK1 inhibition-induced mitotic delay.
  • MEK1-mediated phosphorylation of Myt1 requires an unknown kinase and is independent of RSK, Plk, and CDK1.
  • Myt1 inactivation by MEK1 is crucial for Golgi fragmentation in G2 and subsequent mitotic entry.

Conclusions:

  • Myt1 acts as a crucial mediator of MEK1's effects on the Golgi complex.
  • MEK1-dependent Myt1 inactivation links Golgi fragmentation in G2 to the breakdown of Golgi structures in mitosis.
  • Myt1 serves as a molecular link between Golgi dynamics and cell cycle regulation.

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