title: Oscillatory dynamics of Cdc42 GTPase in the control of polarized growth.
abstract: Cells promote polarized growth by activation of Rho-family protein Cdc42 at the cell membrane. We combined experiments and modeling to study bipolar growth initiation in fission yeast. Concentrations of a fluorescent marker for active Cdc42, Cdc42 protein, Cdc42-activator Scd1, and scaffold protein Scd2 exhibited anticorrelated fluctuations and oscillations with a 5-minute average period at polarized cell tips. These dynamics indicate competition for active Cdc42 or its regulators and the presence of positive and delayed negative feedbacks. Cdc42 oscillations and spatial distribution were sensitive to the amounts of Cdc42-activator Gef1 and to the activity of Cdc42-dependent kinase Pak1, a negative regulator. Feedbacks regulating Cdc42 oscillations and spatial self-organization appear to provide a flexible mechanism for fission yeast cells to explore polarization states and to control their morphology.
authors.affiliation: Department of Molecular and Cellular Pharmacology (R-189), University of Miami Miller School of Medicine, Post Office Box 016189, Miami, FL 33101, USA.
authors.forename: Maitreyi
authors.initials: M
authors.lastname: Das
authors.forename: Tyler
authors.initials: T
authors.lastname: Drake
authors.forename: David J
authors.initials: DJ
authors.lastname: Wiley
authors.forename: Peter
authors.initials: P
authors.lastname: Buchwald
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Vavylonis
authors.forename: Fulvia
authors.initials: F
authors.lastname: Verde
mesh_terms: D018797:Cell Cycle Proteins / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D009154:Mutation; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012568:Schizosaccharomyces / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development*; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism*; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism*; D054462:p21-Activated Kinases / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D020662:Guanine Nucleotide Exchange Factors; D011993:Recombinant Fusion Proteins; D029702:Schizosaccharomyces pombe Proteins; C089769:scd1 protein, S pombe; C089770:scd2 protein, S pombe; D054462:p21-Activated Kinases; C094341:shk1 protein, S pombe; D020764:cdc42 GTP-Binding Protein