Analysis and modeling of cell polarization in budding yeast

Wing Cheong (Jon) Lo
Mathematical Biosciences Institute, The Ohio State University

(April 18, 2013 10:20 AM - 11:15 AM)

Analysis and modeling of cell polarization in budding yeast

Abstract

The Cdc42 GTPase plays a key role in cell polarization in budding yeast. Although previous studies in budding yeast suggested positive feedback loops whereby Cdc42 becomes polarized, these mechanisms do not include spatial cues, neglecting the normal patterns of budding. In this talk, we present a two-equation reaction-diffusion model of cell polarization with a general function form of positive feedback. In the first part, we perform linear stability analysis, in particular Turing stability analysis to the model to derive conditions of parameters for which cell polarity emerges without any spatial cue. In the second part, we combine live cell imaging and mathematical modeling to understand how diploid daughter cells establish polarity preferentially at the pole distal to the previous division site despite the presence of two landmark cues at distal pole and proximal pole. We report that both spatial landmarks and GTP hydrolysis of Cdc42 by Rga1 controls the robust Cdc42-GTP polarization in diploid daughter cells.