| Title: | Yeast G-proteins mediate directional sensing and polarization behaviors in response to changes in pheromone gradient direction |
| Author(s): | Moore TI; Tanaka H; Kim HJ; Jeon NL; Yi TM; |
| Address: | "Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA" |
| ISSN/ISBN: | 1939-4586 (Electronic) 1059-1524 (Print) 1059-1524 (Linking) |
| Abstract: | "Yeast cells polarize by projecting up mating pheromone gradients, a classic cell polarity behavior. However, these chemical gradients may shift direction. We examine how yeast cells sense and respond to a 180(o) switch in the direction of microfluidically generated pheromone gradients. We identify two behaviors: at low concentrations of alpha-factor, the initial projection grows by bending, whereas at high concentrations, cells form a second projection toward the new source. Mutations that increase heterotrimeric G-protein activity expand the bending-growth morphology to high concentrations; mutations that increase Cdc42 activity result in second projections at low concentrations. Gradient-sensing projection bending requires interaction between Gbetagamma and Cdc24, whereas gradient-nonsensing projection extension is stimulated by Bem1 and hyperactivated Cdc42. Of interest, a mutation in Galpha affects both bending and extension. Finally, we find a genetic perturbation that exhibits both behaviors. Overexpression of the formin Bni1, a component of the polarisome, makes both bending-growth projections and second projections at low and high alpha-factor concentrations, suggesting a role for Bni1 downstream of the heterotrimeric G-protein and Cdc42 during gradient sensing and response. Thus we demonstrate that G-proteins modulate in a ligand-dependent manner two fundamental cell-polarity behaviors in response to gradient directional change" |
| Keywords: | "Adaptor Proteins, Signal Transducing/genetics/metabolism Cell Cycle Proteins/*genetics/metabolism Cell Polarity Chemotaxis/drug effects *Gene Expression Regulation, Fungal/drug effects Guanine Nucleotide Exchange Factors/*genetics/metabolism Mating Factor;" |
| Notes: | "MedlineMoore, Travis I Tanaka, Hiromasa Kim, Hyung Joon Jeon, Noo Li Yi, Tau-Mu eng T32 HD060555/HD/NICHD NIH HHS/ HD060555-01/HD/NICHD NIH HHS/ P50 GM076516/GM/NIGMS NIH HHS/ R44 CA093106/CA/NCI NIH HHS/ R43 CA093106/CA/NCI NIH HHS/ P50GM76516/GM/NIGMS NIH HHS/ R01GM75309/GM/NIGMS NIH HHS/ R01 GM075309/GM/NIGMS NIH HHS/ Research Support, N.I.H., Extramural Research Support, U.S. Gov't, Non-P.H.S. 2012/12/18 Mol Biol Cell. 2013 Feb; 24(4):521-34. doi: 10.1091/mbc.E12-10-0739. Epub 2012 Dec 14" |
