PLoS ONE · 2009 · 38 citations · 32 references
Life SciencesCell BiologyMolecular BiologyCytoskeletonMolecular Cell BiologySignal TransductionCell Shape RegulationCell Signaling NetworksCytoskeletal SignalingProtein Kinase CascadesSmall Gtpase SignalingStress Signaling PathwaysActin Cytoskeleton RemodelingActin Cytoskeleton ReorganizationActin DynamicsCell Wall ExpansionGuanosine Triphosphatase RegulationMapk SignalingMitogen-activated Protein Kinase PathwaysMitogen-activated Protein Kinase Signaling
In the yeast Saccharomyces cerevisiae the guanosine triphosphatase (GTPase) Rho1 controls actin polarization and cell wall expansion. When cells are exposed to various environmental stresses that perturb the cell wall, Rho1 activates Pkc1, a mammalian Protein Kinase C homologue, and Mpk1, a mitogen activated protein kinase (MAPK), resulting in actin depolarization and cell wall remodeling. In this study, we demonstrate a novel feedback loop in this Rho1-mediated Pkc1-MAPK pathway that involves regulation of Rom2, the guanine nucleotide exchange factor of Rho1, by Mpk1, the end kinase of the pathway. This previously unrecognized Mpk1-dependent feedback is a critical step in regulating Rho1 function. Activation of this feedback mechanism is responsible for redistribution of Rom2 and cell wall synthesis activity from the bud to cell periphery under stress conditions. It is also required for terminating Rho1 activity toward the Pkc1-MAPK pathway and for repolarizing actin cytoskeleton and restoring growth after the stressed cells become adapted.
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Identification of Yeast Rho1p GTPase as a Regulatory Subunit of 1,3-β-Glucan Synthase
Hiroshi Qadota, C P Python, Shunsuke Inoue et al. · Science · 1996 · 451 citations