1. Evidence for functional links between the Rgd1-Rho3 RhoGAP-GTPase module and Tos2, a protein involved in polarized growth in Saccharomyces cerevisiae.
- Author
-
Claret, Sandra, Roumanie, Olivier, Prouzet-Mauleon, Valérie, Lefebvre, Fabien, Thoraval, Didier, Crouzet, Marc, and Doignon, François
- Subjects
GUANOSINE triphosphatase ,MICROBIAL growth ,SACCHAROMYCES cerevisiae ,CYTOKINESIS ,CARRIER proteins ,CELL cycle ,CELL membranes - Abstract
The Rho GTPase-activating protein Rgd1p positively regulates the GTPase activity of Rho3p and Rho4p, which are involved in bud growth and cytokinesis, respectively, in the budding yeast Saccharomyces cerevisiae. Two-hybrid screening identified Tos2p as a candidate Rgd1p-binding protein. Further analyses confirmed that Tos2p binds to the RhoGAP Rgd1p through its C-terminal region. Both Tos2p and Rgd1p are localized to polarized growth sites during the cell cycle and associated with detergent-resistant membranes. We observed that TOS2 overexpression suppressed rgd1Δ sensitivity to a low pH. In the tos2Δ strain, the amount of GTP-bound Rho3p was increased, suggesting an influence of Tos2p on Rgd1p activity in vivo. We also showed a functional interaction between the TOS2 and the RHO3 genes: TOS2 overexpression partially suppressed the growth defect of rho3-V51 cells at a restrictive temperature. We propose that Tos2p, a protein involved in polarized growth and most probably associated with the plasma membrane, modulates the action of Rgd1p and Rho3p in S. cerevisiae. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF