The Rho GTPase Rho3 Has a Direct Role in Exocytosis That is Distinct from Its Role in Actin Polarity

Overview

Journal Mol Biol Cell

Specialties Cell Biology
Molecular Biology

Date 1999 Dec 10

PMID 10588647

Citations 105

Authors

J E Adamo

G Rossi

P Brennwald

Affiliations

Soon will be listed here.

Abstract

Budding yeast grow asymmetrically by the polarized delivery of proteins and lipids to specific sites on the plasma membrane. This requires the coordinated polarization of the actin cytoskeleton and the secretory apparatus. We identified Rho3 on the basis of its genetic interactions with several late-acting secretory genes. Mutational analysis of the Rho3 effector domain reveals three distinct functions in cell polarity: regulation of actin polarity, transport of exocytic vesicles from the mother cell to the bud, and docking and fusion of vesicles with the plasma membrane. We provide evidence that the vesicle delivery function of Rho3 is mediated by the unconventional myosin Myo2 and that the docking and fusion function is mediated by the exocyst component Exo70. These data suggest that Rho3 acts as a key regulator of cell polarity and exocytosis, coordinating several distinct events for delivery of proteins to specific sites on the cell surface.

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