Exploration and stabilization of Ras1 mating zone: A mechanism with positive and negative feedbacks

• DOI: 10.1371/journal.pcbi.1006317
• Publication Date: 2018-07-20T17:24:22Z
• Authors: Bita Khalili; Laura Merlini; Vincent Vincenzetti; Sophie G. Martin; Dimitrios Vavylonis
• Keywords: CDC42

In mating fission yeast cells, sensing and response to extracellular pheromone concentrations occurs through an exploratory Cdc42 patch that stochastically samples the cell cortex before stabilizing towards a partner. Active Ras1 (Ras1-GTP), upstream regulator of Cdc42, Gap1, GTPase-activating protein for Ras1, localize at patch. We developed reaction-diffusion model appearance disappearance with positive feedback by Guanine nucleotide Exchange Factor (GEF) Gap1 inhibition. The is based on new estimates Ras1-GDP, Ras1-GTP diffusion coefficients rates cytoplasmic exchange studied FRAP. reproduces behavior lack in cells lacking Gap1. Transition stable can occur change constants or local increase rate constants. predicts size number patches depend strength negative feedbacks. Measurements overexpressing GEF are consistent model.