Interaction between bud-site selection and polarity-establishment machineries in budding yeast.

Wu, Chi-Fang, Savage, Natasha S ORCID: 0000-0002-6831-6533 and Lew, Daniel J
(2013) Interaction between bud-site selection and polarity-establishment machineries in budding yeast. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 368 (1629). 20130006-.

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Saccharomyces cerevisiae yeast cells polarize in order to form a single bud in each cell cycle. Distinct patterns of bud-site selection are observed in haploid and diploid cells. Genetic approaches have identified the molecular machinery responsible for positioning the bud site: during bud formation, specific locations are marked with immobile landmark proteins. In the next cell cycle, landmarks act through the Ras-family GTPase Rsr1 to promote local activation of the conserved Rho-family GTPase, Cdc42. Additional Cdc42 accumulates by positive feedback, creating a concentrated patch of GTP-Cdc42, which polarizes the cytoskeleton to promote bud emergence. Using time-lapse imaging and mathematical modelling, we examined the process of bud-site establishment. Imaging reveals unexpected effects of the bud-site-selection system on the dynamics of polarity establishment, raising new questions about how that system may operate. We found that polarity factors sometimes accumulate at more than one site among the landmark-specified locations, and we suggest that competition between clusters of polarity factors determines the final location of the Cdc42 cluster. Modelling indicated that temporally constant landmark-localized Rsr1 would weaken or block competition, yielding more than one polarity site. Instead, we suggest that polarity factors recruit Rsr1, effectively sequestering it from other locations and thereby terminating landmark activity.

Item Type: Article
Additional Information: ## TULIP Type: Articles/Papers (Journal) ##
Uncontrolled Keywords: Cell Surface Extensions, Cytoskeleton, Saccharomycetales, rab GTP-Binding Proteins, cdc42 GTP-Binding Protein, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Membrane Proteins, Microscopy, Confocal, Cell Polarity, Models, Biological, Image Processing, Computer-Assisted, Time-Lapse Imaging
Depositing User: Symplectic Admin
Date Deposited: 07 Apr 2017 14:18
Last Modified: 15 Mar 2024 14:15
DOI: 10.1098/rstb.2013.0006
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