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Spatiotemporal Analysis of Cytokinetic Events in Fission Yeast
Published on: February 20, 2017
Cdc42 regulates multiple membrane traffic events in fission yeast
Miguel Estravís1, Sergio A Rincón, Beatriz Santos
1Instituto de Biología funcional y Genómica, Consejo Superior de Investigaciones Científicas CSIC/Departamento de Microbiología y Genética, Universidad de Salamanca, 30007 Salamanca, Spain.
Traffic (Copenhagen, Denmark)
|September 9, 2011
Summary
Fission yeast Cdc42 is crucial for cell growth and membrane trafficking. Disrupting Cdc42 impairs secretion and vacuole formation, but proteins like Pob1 and Rho3 can restore these functions.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Fission yeast Cdc42 is essential for polarized growth, regulating actin cable assembly and formin activation.
- The cdc42L160S allele in fission yeast causes thermosensitive growth defects.
- Membrane trafficking, including secretion and vacuole dynamics, is vital for cell viability.
Purpose of the Study:
- To investigate the role of Cdc42 in membrane trafficking independent of its role in actin cable assembly.
- To identify factors that can rescue defects caused by the cdc42L160S mutation.
- To elucidate the relationship between Cdc42, Pob1, Rho3, and membrane trafficking pathways.
Main Methods:
- Utilized a thermosensitive fission yeast strain (cdc42L160S).
- Assessed membrane trafficking by measuring acid phosphatase (AP) secretion and observing vesicle accumulation and vacuole morphology.
- Examined the localization of the exocyst complex.
- Investigated the effects of overproducing Pob1, Rho3, psy1(+), and ypt2(+) on cdc42L160S phenotypes.
- Analyzed rescue of actin cable defects and vacuole formation.
Main Results:
- The cdc42L160S strain exhibited membrane traffic defects, including reduced AP secretion, vesicle accumulation, and vacuole fragmentation, independently of actin cable defects.
- Exocyst localization to the cell tips was impaired in cdc42L160S cells.
- Overproduction of Pob1 or Rho3 suppressed thermosensitive growth, restored exocyst localization, and rescued AP secretion.
- Rho3 and Pob1 also rescued vacuole formation defects.
- Overexpression of psy1(+) or ypt2(+) rescued growth but not actin cables or exocyst localization.
- Pob1, but not Rho3, restored actin cables.
Conclusions:
- Cdc42 plays a critical role in membrane trafficking and fusion, impacting polarized secretion, endosome recycling, and vacuole formation.
- The scaffold protein Pob1 is essential for Cdc42-mediated membrane trafficking and fusion.
- Rho3, Psy1, and Ypt2 are involved in specific aspects of membrane trafficking and cell growth, but Cdc42 and Pob1 have broader roles.
- These findings highlight the intricate coordination between the actin cytoskeleton and membrane trafficking machinery in fission yeast.
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