Abstract
The localization (or polarization) of proteins on the membrane during the mating of budding yeast (Saccharomyces cerevisiae) is an important model system for understanding simple pattern formation within cells. While there are many existing mathematical models of polarization, for both budding and mating, there are still many aspects of this process that are not well understood. In this paper we set out to elucidate the effect that the geometry of the cell can have on the dynamics of certain models of polarization. Specifically, we look at several spatial stochastic models of Cdc42 polarization that have been adapted from published models, on a variety of tip-shaped geometries, to replicate the shape change that occurs during the growth of the mating projection. We show here that there is a complex interplay between the dynamics of polarization and the shape of the cell. Our results show that while models of polarization can generate a stable polarization cap, its localization at the tip of mating projections is unstable, with the polarization cap drifting away from the tip of the projection in a geometry dependent manner. We also compare predictions from our computational results to experiments that observe cells with projections of varying lengths, and track the stability of the polarization cap. Lastly, we examine one model of actin polarization and show that it is unlikely, at least for the models studied here, that actin dynamics and vesicle traffic are able to overcome this effect of geometry.
Highlights
The polarization of proteins during the mating of Saccharomyces cerevisiae is a well-studied, yet not fully understood, example of pattern formation in biology
One useful model system is the mating of yeast cells, where a localization of proteins on the membrane leads to actin cable formation, vesicle traffic, changes in material properties
Haploid yeast cells respond to a gradient of mating pheromone via a cascade of intracellular protein reactions, culminating in a localization of key proteins on the membrane that facilitate actin cable formation and vesicle transport [1]
Summary
The polarization of proteins during the mating of Saccharomyces cerevisiae is a well-studied, yet not fully understood, example of pattern formation in biology. At varying levels of mathematical complexity, for the different levels of polarization in both budding and mating. The majority of models have been developed to study the dynamics of the main polarity regulator, the Rho GTPase Cdc42 [2,3,4], the formation of actin cables and the polarisome [5,6,7], or the interaction between the two [6, 8, 9]. The literature for models of polarization in yeast is vast and often contains conflicting results regarding the role of different mechanisms. Stochastic dynamics can more robustly reproduce a highly polarized phenotype and track a moving pheromone input [5]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
