Bud3 activates Cdc42 to establish a proper growth site in budding yeast.

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.
Mesh Terms:
Amino Acid Sequence, Cell Division, Cell Polarity, Enzyme Activation, G1 Phase Cell Cycle Checkpoints, Molecular Sequence Data, Protein Structure, Tertiary, Protein Transport, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Time-Lapse Imaging, cdc42 GTP-Binding Protein, Saccharomyces cerevisiae
J. Cell Biol.
Date: Jul. 07, 2014
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