title: GDI-mediated cell polarization in yeast provides precise spatial and temporal control of Cdc42 signaling.
abstract: Cell polarization is a prerequisite for essential processes such as cell migration, proliferation or differentiation. The yeast Saccharomyces cerevisiae under control of the GTPase Cdc42 is able to polarize without the help of cytoskeletal structures and spatial cues through a pathway depending on its guanine nucleotide dissociation inhibitor (GDI) Rdi1. To develop a fundamental understanding of yeast polarization we establish a detailed mechanistic model of GDI-mediated polarization. We show that GDI-mediated polarization provides precise spatial and temporal control of Cdc42 signaling and give experimental evidence for our findings. Cell cycle induced changes of Cdc42 regulation enhance positive feedback loops of active Cdc42 production, and thereby allow simultaneous switch-like regulation of focused polarity and Cdc42 activation. This regulation drives the direct formation of a unique polarity cluster with characteristic narrowing dynamics, as opposed to the previously proposed competition between transient clusters. As the key components of the studied system are conserved among eukaryotes, we expect our findings also to apply to cell polarization in other organisms.
authors.affiliation: Arnold Sommerfeld Center for Theoretical Physics (ASC) and Center for NanoScience (CeNS), Department of Physics, Ludwig-Maximilians-Universität München, München, Germany.
authors.forename: Ben
authors.initials: B
authors.lastname: Klünder
authors.affiliation: Max Planck Institute of Biochemistry, Cellular Dynamics and Cell Patterning, Martinsried, Germany.
authors.forename: Tina
authors.initials: T
authors.lastname: Freisinger
authors.affiliation: Max Planck Institute of Biochemistry, Cellular Dynamics and Cell Patterning, Martinsried, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Wedlich-Söldner
authors.affiliation: Arnold Sommerfeld Center for Theoretical Physics (ASC) and Center for NanoScience (CeNS), Department of Physics, Ludwig-Maximilians-Universität München, München, Germany.
authors.forename: Erwin
authors.initials: E
authors.lastname: Frey
mesh_terms: D016764:Cell Polarity; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000201:enzymology*; D015398:Signal Transduction / Q000502:physiology*; D020846:cdc42 GTP-Binding Protein, Saccharomyces cerevisiae / Q000378:metabolism*
chemical_list: D020730:Guanine Nucleotide Dissociation Inhibitors; D020846:cdc42 GTP-Binding Protein, Saccharomyces cerevisiae