Rho GTPases are important regulators of polarity in eukaryotic cells. In yeast they are involved in regulating the docking and fusion of secretory vesicles with the cell surface. Our analysis of a Rho3 mutant that is unable to interact with the Exo70 subunit of the exocyst reveals a normal polarization of the exocyst complex as well as other polarity markers. We also find that there is no redundancy between the Rho3–Exo70 and Rho1–Sec3 pathways in the localization of the exocyst. This suggests that Rho3 and Cdc42 act to polarize exocytosis by activating the exocytic machinery at the membrane without the need to first recruit it to sites of polarized growth. Consistent with this model, we find that the ability of Rho3 and Cdc42 to hydrolyze GTP is not required for their role in secretion. Moreover, our analysis of the Sec3 subunit of the exocyst suggests that polarization of the exocyst may be a consequence rather than a cause of polarized exocytosis.
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15 August 2005
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August 15 2005
Rho GTPase regulation of exocytosis in yeast is independent of GTP hydrolysis and polarization of the exocyst complex
Olivier Roumanie,
Olivier Roumanie
1Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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Hao Wu,
Hao Wu
1Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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Jeffrey N. Molk,
Jeffrey N. Molk
2Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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Guendalina Rossi,
Guendalina Rossi
1Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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Kerry Bloom,
Kerry Bloom
2Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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Patrick Brennwald
Patrick Brennwald
1Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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Olivier Roumanie
1Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
Hao Wu
1Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
Jeffrey N. Molk
2Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
Guendalina Rossi
1Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
Kerry Bloom
2Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
Patrick Brennwald
1Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
Correspondence to Patrick Brennwald: [email protected]
O. Roumanie's present address is Laboratoire de Biologie Moléculaire et Séquençage, Institut de Biochimie et Genetique Cellulaires, 33077 Bordeaux, France.
Abbreviations used in this paper: DIC, differential interference contrast; RBD, Rho-binding domain.
Received:
April 19 2005
Accepted:
July 12 2005
Online ISSN: 1540-8140
Print ISSN: 0021-9525
The Rockefeller University Press
2005
J Cell Biol (2005) 170 (4): 583–594.
Article history
Received:
April 19 2005
Accepted:
July 12 2005
Citation
Olivier Roumanie, Hao Wu, Jeffrey N. Molk, Guendalina Rossi, Kerry Bloom, Patrick Brennwald; Rho GTPase regulation of exocytosis in yeast is independent of GTP hydrolysis and polarization of the exocyst complex . J Cell Biol 15 August 2005; 170 (4): 583–594. doi: https://doi.org/10.1083/jcb.200504108
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