A GDP/GTP Exchange Factor Involved in Linking a Spatial Landmark to Cell Polarity

Kang, Pil Jung; Sanson, Anthony; Lee, Bongyong; Park, Hay-Oak

doi:10.1126/science.1060360

Cited by 102 publications

(126 citation statements)

References 27 publications

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“…These results suggest that overexpression of a GTP-locked form of Rsr1 recruits Cdc24 uniformly to the plasma membrane. DISCUSSION We showed previously that the regulators of Rsr1, Bud2 and Bud5, are localized to the presumptive bud site and to discrete sites during the cell cycle and that their localization is essential for selection of a specific site for growth (10,11). Bud2 and Bud5 cannot maintain their localization at the proper bud site in rsr1⌬ cells.…”

Section: Localization Of the Rsr1/bud1 Gtpase 26723mentioning

confidence: 99%

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Localization of the Rsr1/Bud1 GTPase Involved in Selection of a Proper Growth Site in Yeast

Park¹,

Kang²,

Rachfal³

2002

Journal of Biological Chemistry

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Yeast cells organize their actin cytoskeleton in a highly polarized manner during vegetative growth. The Ras-like GTPase Rsr1/Bud1 and its regulators are required for selection of a specific site for growth. Here we showed that Rsr1/Bud1 was broadly distributed on the plasma membrane and highly concentrated at the incipient bud site and polarized growth sites. We also showed that localization of Cdc24, a guanine nucleotide exchange factor for the Cdc42 GTPase, to the proper bud site was dependent on Rsr1/Bud1. Surprisingly, Rsr1/ Bud1 also localized to intracellular membranes. A mutation in the lysine repeat in the hypervariable region of Rsr1/Bud1 specifically abolished its plasma membrane localization, whereas a mutation at the CAAX motif eliminated both plasma membrane and internal membrane association of Rsr1/Bud1. Thus the lysine repeat and the CAAX motif of Rsr1/Bud1 are important for its localization to the plasma membrane and to the polarized growth sites. This localization of Rsr1/Bud1 is essential for its function in proper bud site selection because both mutations resulted in random bud site selection.Cells of the budding yeast Saccharomyces cerevisiae undergo oriented cell division by selecting a specific site for polarized growth on their cell cortex (1-3). Haploid a and ␣ cells bud in an axial pattern, whereas diploid a/␣ cells bud in a bipolar pattern. The GTPase module consisting of Rsr1/Bud1 (Rsr1 hereafter), its GDP-GTP exchange factor Bud5, and its GTPase-activating protein Bud2 is essential for selecting the proper site for polarized growth in both haploid and diploid cells (4 -7). Based on genetic and biochemical data, we proposed previously that the Rsr1 GTPase module directs bud site assembly to occur at specific locations by recruiting components such as Cdc24 required for bud formation to that site (8). Recruiting these proteins to the presumptive bud site is thought to direct the cytoskeleton and secretory apparatus toward the bud site, thereby restricting new growth to the bud (9). One of the key questions in understanding the molecular basis of cell polarity is how specific sites for actin polymerization are determined.To understand the mechanism of action of the Rsr1 GTPase module, it is crucial to determine whether any of its components are localized to the presumptive bud site. We reported previously that both Bud2 and Bud5 are localized to the presumptive bud site and to discrete sites during the cell cycle (10, 11). This localization is essential for selection of a specific site for growth. Here we report that Rsr1 is broadly distributed on the plasma membrane and is highly concentrated at the incipient bud site and polarized growth sites. Mutational studies indicated that the lysine repeat in the hypervariable region and the CAAX motif of Rsr1 are important for its localization and its role in selection of a proper site for growth. We also show that localization of Cdc24, a guanine nucleotide exchange factor for Cdc42, to the proper bud site is dependent on Rsr1. EXPERIMENTAL PR...

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Section: Localization Of the Rsr1/bud1 Gtpase 26723mentioning

confidence: 99%

“…We reported previously that both Bud2 and Bud5 are localized to the presumptive bud site and to discrete sites during the cell cycle (10,11). This localization is essential for selection of a specific site for growth.…”

mentioning

confidence: 99%

Localization of the Rsr1/Bud1 GTPase Involved in Selection of a Proper Growth Site in Yeast

Park¹,

Kang²,

Rachfal³

2002

Journal of Biological Chemistry

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“…During budding, Cdc24 is also a target of regulation dictating the orientation of bud formation relative to the previous bud scar (Figure 1). Cdc24 is activated and recruited to the plasma membrane partly through interaction with the GTP-bound Ras type GTPase Rsr1 [81][82][83]. Involvement of GTPase cascades is a recurring theme in spatial organization.…”

Section: Regulatory Linkages Affecting the Cdc42 Modulementioning

confidence: 99%

Yeast and fungal morphogenesis from an evolutionary perspective

Wedlich‐Söldner

2008

Seminars in Cell & Developmental Biology

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Cellular morphogenesis is a complex process and molecular studies in the last few decades have amassed a large amount of information that is difficult to grasp in any completeness. Fungal systems, in particular the budding and fission yeasts, have been important players in unravelling the basic structural and regulatory elements involved in a wide array of cellular processes. In this article, we address the design principles underlying the various processes of yeast and fungal morphogenesis. We attempt to explain the apparent molecular complexity from the perspective of the evolutionary theory of "facilitated variation". Following a summary of some of the most studied morphogenetic phenomena, we discuss, using recent examples, the underlying core processes and their associated "weak" regulatory linkages that bring about variation in morphogenetic phenotypes.

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“…Fluorescence microscopy and bimolecular fluorescence complementation Image acquisition of GFP-Rho1 was carried out essentially as previously described (Kang et al 2001) using a Nikon E800 microscope (Nikon, Tokyo, Japan) fitted with a 100· oil-immersion objective (N.A. = 1.30), a Uniblitz electronic shutter, a Prior Z-axis drive, and a Hamamatsu Orca ER cooled charge-coupled device.…”

Section: Integrated Membrane Yeast Two-hybrid Analysismentioning

confidence: 99%

The Rho1 GTPase Acts Together With a Vacuolar Glutathione S-Conjugate Transporter to Protect Yeast Cells From Oxidative Stress

Lee

Singh²,

Snider

et al. 2011

Genetics

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Maintenance of redox homeostasis is critical for the survival of all aerobic organisms. In the budding yeast Saccharomyces cerevisiae, as in other eukaryotes, reactive oxygen species (ROS) are generated during metabolism and upon exposure to environmental stresses. The abnormal production of ROS triggers defense mechanisms to avoid the deleterious consequence of ROS accumulation. Here, we show that the Rho1 GTPase is necessary to confer resistance to oxidants in budding yeast. Temperature-sensitive rho1 mutants (rho1 ts ) are hypersensitive to oxidants and exhibit high accumulation of ROS even at a semipermissive temperature. Rho1 associates with Ycf1, a vacuolar glutathione S-conjugate transporter, which is important for heavy metal detoxification in yeast. Rho1 and Ycf1 exhibit a two-hybrid interaction with each other and form a bimolecular fluorescent complex on the vacuolar membrane. A fluorescent-based complementation assay suggests that the GTP-bound Rho1 associates with Ycf1 and that their interaction is enhanced upon exposure to hydrogen peroxide. The rho1 ts mutants also exhibit hypersensitivity to cadmium, while cells carrying a deletion of YCF1 or mutations in a component of the Pkc1-MAP kinase pathway exhibit little or minor sensitivity to oxidants. We thus propose that Rho1 protects yeast cells from oxidative stress by regulating multiple downstream targets including Ycf1. Since both Rho1 and Ycf1 belong to highly conserved families of proteins, similar mechanisms may exist in other eukaryotes.

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A GDP/GTP Exchange Factor Involved in Linking a Spatial Landmark to Cell Polarity

Cited by 102 publications

References 27 publications

Localization of the Rsr1/Bud1 GTPase Involved in Selection of a Proper Growth Site in Yeast

Localization of the Rsr1/Bud1 GTPase Involved in Selection of a Proper Growth Site in Yeast

Yeast and fungal morphogenesis from an evolutionary perspective

The Rho1 GTPase Acts Together With a Vacuolar Glutathione S-Conjugate Transporter to Protect Yeast Cells From Oxidative Stress

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