Gβ promotes pheromone receptor polarization and yeast chemotropism by inhibiting receptor phosphorylation

Amber Ismael, Wei Tian, Nicholas Waszczak, Xin Wang, Youfang Cao, Dmitry Suchkov, Eli Bar, Metodi V. Metodiev, Jie Liang, Robert A. Arkowitz, David E. Stone

Research output: Contribution to journalArticlepeer-review

Abstract

Gradient-directed cell migration (chemotaxis) and growth (chemotropism) are processes that are essential to the development and life cycles of all species. Cells use surface receptors to sense the shallow chemical gradients that elicit chemotaxis and chemotropism. Slight asymmetries in receptor activation are amplified by downstream signaling systems, which ultimately induce dynamic reorganization of the cytoskeleton. During the mating response of budding yeast, a model chemotropic system, the pheromone receptors on the plasma membrane polarize to the side of the cell closest to the stimulus. Although receptor polarization occurs before and independently of actin cable-dependent delivery of vesicles to the plasma membrane (directed secretion), it requires receptor internalization. Phosphorylation of pheromone receptors by yeast casein kinase 1 or 2 (Yck1/2) stimulates their internalization. We showed that the pheromone-responsive Gβγ dimer promotes the polarization of the pheromone receptor by interacting with Yck1/2 and locally inhibiting receptor phosphorylation. We also found that receptor phosphorylation is essential for chemotropism, independently of its role in inducing receptor internalization. A mathematical model supports the idea that the interaction between Gβγ and Yck1/2 results in differential phosphorylation and internalization of the pheromone receptor and accounts for its polarization before the initiation of directed secretion.

Original languageEnglish (US)
Article numberra38
JournalScience Signaling
Volume9
Issue number423
DOIs
StatePublished - Apr 12 2016
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology

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