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Opposing roles for actin in Cdc42p polarization
Javier E Irazoqui1, Audrey S Howell, Chandra L Theesfeld
1Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
Molecular Biology of the Cell
|December 24, 2004
Summary
Partial actin depolymerization disperses Cdc42p in yeast cells, requiring actin cables to maintain cell polarity. Bud formation increases Cdc42p resistance to dispersal, highlighting differences between cell states.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Cdc42p, a GTPase, regulates cell polarity in animal and fungal cells.
- Previous studies indicated Cdc42p polarization is actin-independent in budding yeast.
Purpose of the Study:
- To investigate the effect of partial actin depolymerization on Cdc42p distribution.
- To elucidate the mechanisms maintaining Cdc42p polarity.
Main Methods:
- Experimental manipulation of actin cytoskeleton integrity in yeast cells.
- Microscopic observation of Cdc42p localization and actin structures.
Main Results:
- Partial actin depolymerization, unlike complete depolymerization, causes Cdc42p dispersal in unbudded cells.
- Actin-dependent endocytosis contributes to Cdc42p dispersal.
- Actin cables are essential for counteracting dispersal and maintaining Cdc42p polarity.
- Polarized Cdc42p is more resistant to dispersal in budded cells compared to unbudded cells.
Conclusions:
- Cdc42p polarization is initially actin-independent, but its maintenance involves actin cables to counteract endocytosis-driven dispersal.
- Distinct mechanisms govern Cdc42p polarity organization in unbudded versus budded yeast cells.