title: Feedback inhibition on cell wall integrity signaling by Zds1 involves Gsk3 phosphorylation of a cAMP-dependent protein kinase regulatory subunit.
abstract: We report here that budding yeast cAMP-dependent protein kinase (cAPK) is controlled by heat stress. A rise in temperature from 30 to 37 degrees C was found to result in both a higher expression and an increased cytoplasmic localization of its regulatory subunit Bcy1. Both of these effects required phosphorylation of serines located in its localization domain. Surprisingly, classic cAPK-controlled processes were found to be independent of Bcy1 phosphorylation, indicating that these modifications do not affect cAPK activity as such. Alternatively, phosphorylation may recruit cAPK to, and thereby control, a specific subset of (perhaps novel) cAPK targets that are presumably localized extranuclearly. Zds1 and Zds2 may play a role in this process, since these were found required to retain hyperphosphorylated Bcy1 in the cytoplasm at 37 degrees C. Mck1, a homologue of mammalian glycogen synthase kinase 3 and a downstream component of the heat-activated Pkc1-Slt2/Mpk1 cell wall integrity pathway, is partly responsible for hyperphosphorylations of Bcy1. Remarkably, Zds1 appears to act as a negative regulator of cell wall integrity signaling, and this activity is dependent in part on the phosphorylation status of Bcy1. Thus, Mck1 phosphorylation of Bcy1 and Zds1 may constitute an unprecedented negative feedback control on the cell wall integrity-signaling pathway.
authors.affiliation: Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Katholieke Universiteit Leuven, Belgium.
authors.forename: Gerard
authors.initials: G
authors.lastname: Griffioen
authors.forename: Steve
authors.initials: S
authors.lastname: Swinnen
authors.forename: Johan M
authors.initials: JM
authors.lastname: Thevelein
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D002473:Cell Wall / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D025461:Feedback, Physiological; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D006358:Hot Temperature; D010766:Phosphorylation; D021122:Protein Subunits / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism / Q000502:physiology; D015398:Signal Transduction
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D021122:Protein Subunits; D029701:Saccharomyces cerevisiae Proteins; C101740:ZDS1 protein, S cerevisiae; C101741:ZDS2 protein, S cerevisiae; D011505:Protein-Tyrosine Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D038362:Glycogen Synthase Kinase 3; C068124:MCK1 protein, S cerevisiae