Ratiometric GPCR signaling enables directional sensing in yeast.

Published online

Journal Article

Accurate detection of extracellular chemical gradients is essential for many cellular behaviors. Gradient sensing is challenging for small cells, which can experience little difference in ligand concentrations on the up-gradient and down-gradient sides of the cell. Nevertheless, the tiny cells of the yeast Saccharomyces cerevisiae reliably decode gradients of extracellular pheromones to find their mates. By imaging the behavior of polarity factors and pheromone receptors, we quantified the accuracy of initial polarization during mating encounters. We found that cells bias the orientation of initial polarity up-gradient, even though they have unevenly distributed receptors. Uneven receptor density means that the gradient of ligand-bound receptors does not accurately reflect the external pheromone gradient. Nevertheless, yeast cells appear to avoid being misled by responding to the fraction of occupied receptors rather than simply the concentration of ligand-bound receptors. Such ratiometric sensing also serves to amplify the gradient of active G protein. However, this process is quite error-prone, and initial errors are corrected during a subsequent indecisive phase in which polarity clusters exhibit erratic mobile behavior.

Full Text

Duke Authors

Cited Authors

  • Henderson, NT; Pablo, M; Ghose, D; Clark-Cotton, MR; Zyla, TR; Nolen, J; Elston, TC; Lew, DJ

Published Date

  • October 2019

Published In

Volume / Issue

  • 17 / 10

Start / End Page

  • e3000484 -

PubMed ID

  • 31622333

Pubmed Central ID

  • 31622333

Electronic International Standard Serial Number (EISSN)

  • 1545-7885

Digital Object Identifier (DOI)

  • 10.1371/journal.pbio.3000484

Language

  • eng

Conference Location

  • United States