title: Hypotonic stress-induced calcium signaling in Saccharomyces cerevisiae involves TRP-like transporters on the endoplasmic reticulum membrane.
abstract: Saccharomyces cerevisiae cells respond to hypotonic stress (HTS) by a cytosolic calcium rise, either generated by an influx of calcium from extracellular medium, when calcium is available, or by a release from intracellular stores in scarcity of extracellular calcium. Calcium release from intracellular compartments is peculiarly inhibited by external calcium in a calcineurin-independent and Cch1-, but not Mid1-, driven manner. HTS-induced calcium release is also negatively regulated by the ER protein Cls2 and involves a poorly characterized protein, FLC2/YAL053W gene product, previously proposed to be required for FAD transport in the ER, albeit, due to its molecular features, it was also previously classified as an ion transporter. A computational analysis revealed that this gene and its three homologs in S. cerevisiae, together with previously identified Schizosaccharomyces pombe pkd2 and Neurospora crassa calcium-related spray protein, belong to a fungal branch of TRP-like ion transporters related to human mucolipin and polycystin 2 calcium transporters. Moreover, disruption of FLC2 gene confers severe sensitivity to Calcofluor white and hyper-activation of the cell wall integrity MAPK cascade, suggesting a role in cell wall maintenance as previously suggested for the fission yeast homolog. Perturbation in cytosolic resting calcium concentration and hyper-activation of calcineurin in exponentially growing cells suggest a role for this transporter in calcium homeostasis in yeast.
authors.affiliation: Department of Biotechnology and Biosciences, University of Milano-Bicocca, P.za della Scienza 2, 20126 Milan, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Rigamonti
authors.affiliation: Department of Biotechnology and Biosciences, University of Milano-Bicocca, P.za della Scienza 2, 20126 Milan, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Groppi
authors.affiliation: Department of Biotechnology and Biosciences, University of Milano-Bicocca, P.za della Scienza 2, 20126 Milan, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Belotti
authors.affiliation: Department of Biotechnology and Biosciences, University of Milano-Bicocca, P.za della Scienza 2, 20126 Milan, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Ambrosini
authors.affiliation: Department of Biotechnology and Biosciences, University of Milano-Bicocca, P.za della Scienza 2, 20126 Milan, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Filippi
authors.affiliation: Department of Biotechnology and Biosciences, University of Milano-Bicocca, P.za della Scienza 2, 20126 Milan, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Martegani
authors.affiliation: Department of Biotechnology and Biosciences, University of Milano-Bicocca, P.za della Scienza 2, 20126 Milan, Italy. Electronic address: renata.tisi@unimib.it.
authors.forename: R
authors.initials: R
authors.lastname: Tisi
mesh_terms: D019703:Calcineurin / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism*; D020013:Calcium Signaling; D002135:Calcium-Binding Proteins / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009154:Mutation; D009997:Osmotic Pressure; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D050052:TRPC Cation Channels / Q000235:genetics / Q000378:metabolism
chemical_list: C108765:CCH1 protein, S cerevisiae; C086192:CSG2 protein, S cerevisiae; D015220:Calcium Channels; D002135:Calcium-Binding Proteins; C090463:MID1 protein, S cerevisiae; D008562:Membrane Glycoproteins; D029701:Saccharomyces cerevisiae Proteins; D050052:TRPC Cation Channels; C446509:Yvc1 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases; C072724:SLT2 protein, S cerevisiae; D019703:Calcineurin; D002118:Calcium
keywords: Budding yeast; Mucolipin like calcium channels; Osmotic shock; PKD2 like calcium channels; Polycystin 2 like calcium channels; TRPML; TRPP