Bud3 activates Cdc42 to establish a proper growth site in budding yeast
نویسندگان
چکیده
Cell polarization occurs along a single axis that is generally determined by a spatial cue, yet the underlying mechanism is poorly understood. Using biochemical assays and live-cell imaging, we show that cell polarization to a proper growth site requires activation of Cdc42 by Bud3 in haploid budding yeast. Bud3 catalyzes the release of guanosine diphosphate (GDP) from Cdc42 and elevates intracellular Cdc42-guanosine triphosphate (GTP) levels in cells with inactive Cdc24, which has as of yet been the sole GDP-GTP exchange factor for Cdc42. Cdc42 is activated in two temporal steps in the G1 phase: the first depends on Bud3, whereas subsequent activation depends on Cdc24. Mutational analyses suggest that biphasic activation of Cdc42 in G1 is necessary for assembly of a proper bud site. Biphasic activation of Cdc42 or Rac GTPases may be a general mechanism for spatial cue-directed cell polarization in eukaryotes.
منابع مشابه
The fluid dynamics of collective cell migration
Budding yeast do the Cdc42 two-step T wo different proteins sequentially activate Cdc42 to ensure yeast form a bud at the right place, Kang et al. reveal. Haploid S. cerevisiae cells form new buds immediately adjacent to the division site from the previous cell cycle. The new bud's position is determined by a protein complex called the axial landmark, which assembles at the mother–bud neck of y...
متن کاملRegulation of Cdc42 polarization by the Rsr1 GTPase and Rga1, a Cdc42 GTPase-activating protein, in budding yeast.
Cdc42 plays a central role in establishing polarity in yeast and animals, yet how polarization of Cdc42 is achieved in response to spatial cues is poorly understood. Using live-cell imaging, we found distinct dynamics of Cdc42 polarization in haploid budding yeast in correlation with two temporal steps of the G1 phase. The position at which the Cdc42-GTP cluster develops changes rapidly around ...
متن کاملPolarization of Diploid Daughter Cells Directed by Spatial Cues and GTP Hydrolysis of Cdc42 in Budding Yeast
Cell polarization occurs along a single axis that is generally determined by a spatial cue. Cells of the budding yeast exhibit a characteristic pattern of budding, which depends on cell-type-specific cortical markers, reflecting a genetic programming for the site of cell polarization. The Cdc42 GTPase plays a key role in cell polarization in various cell types. Although previous studies in budd...
متن کاملThe Rsr1/Bud1 GTPase Interacts with Itself and the Cdc42 GTPase during Bud-Site Selection and Polarity Establishment in Budding Yeast
Cell polarization occurs along a single axis that is generally determined in response to spatial cues. In budding yeast, the Rsr1 GTPase and its regulators direct the establishment of cell polarity at the proper cortical location in response to cell type-specific cues. Here we use a combination of in vivo and in vitro approaches to understand how Rsr1 polarization is established. We find that R...
متن کاملSelection of axial growth sites in yeast requires Axl2p, a novel plasma membrane glycoprotein.
Spa2p and Cdc10p both participate in bud site selection and cell morphogenesis in yeast, and spa2delta cdc10-10 cells are inviable. To identify additional components important for these processes in yeast, a colony-sectoring assay was used to isolate high-copy suppressors of the spa2delda cdc10-10 lethality. One such gene, AXL2, has been characterized in detail. axl2 cells are defective in bud ...
متن کامل