Autor: |
Clark-Cotton MR; Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27708., Henderson NT; Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27708., Pablo M; Department of Chemistry, Chapel Hill, NC 27599.; Program in Molecular and Cellular Biophysics, Chapel Hill, NC 27599., Ghose D; Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27708., Elston TC; Department of Pharmacology and Computational Medicine Program, UNC Chapel Hill, Chapel Hill, NC 27599., Lew DJ; Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27708. |
Abstrakt: |
Yeast decode pheromone gradients to locate mating partners, providing a model for chemotropism. How yeast polarize toward a single partner in crowded environments is unclear. Initially, cells often polarize in unproductive directions, but then they relocate the polarity site until two partners' polarity sites align, whereupon the cells "commit" to each other by stabilizing polarity to promote fusion. Here we address the role of the early mobile polarity sites. We found that commitment by either partner failed if just one partner was defective in generating, orienting, or stabilizing its mobile polarity sites. Mobile polarity sites were enriched for pheromone receptors and G proteins, and we suggest that such sites engage in an exploratory search of the local pheromone landscape, stabilizing only when they detect elevated pheromone levels. Mobile polarity sites were also enriched for pheromone secretion factors, and simulations suggest that only focal secretion at polarity sites would produce high pheromone concentrations at the partner's polarity site, triggering commitment. |