title: Neuronal calcium sensor-1 (Ncs1p) is up-regulated by calcineurin to promote Ca2+ tolerance in fission yeast.
abstract: Neuronal calcium sensor (NCS) proteins regulate signal transduction and are highly conserved from yeast to humans. NCS homolog in fission yeast (Ncs1p) is essential for cell growth under extreme Ca(2+) conditions. Ncs1p expression increases approximately 100-fold when fission yeast grows in high extracellular Ca(2+) (>0.1 M). Here, we show that Ca(2+)-induced expression of Ncs1p is controlled at the level of transcription. Transcriptional reporter assays show that ncs1 promoter activity increased 30-fold when extracellular Ca(2+) was raised to 0.1 M and was highly Ca(2+)-specific. Ca(2+)-dependent transcription of ncs1 is abolished by the calcineurin inhibitor (FK506) and by knocking out the calcineurin target, prz1. Thus, Ca(2+)-induced expression of Ncs1p is linked to the calcineurin/prz1 stress response. The Ca(2+)-responsive ncs1 promoter region consists of 130 nucleotides directly upstream from the start codon and contains tandem repeats of the sequence, 5'-caact-3', that binds to Prz1p. The Ca(2+)-sensitive ncs1Delta phenotype is rescued by a yam8 null mutation, suggesting a possible interaction between Ncs1p and the Ca(2+) channel, Yam8p. Ca(2+) uptake and Ncs1p binding to yeast membranes are both decreased in yam8Delta, suggesting Ca(2+)-induced binding of Ncs1p to Yam8p results in channel closure. We propose that Ncs1p promotes Ca(2+) tolerance in fission yeast, in part by cytosolic Ca(2+) buffering and perhaps by negatively regulating the Yam8p Ca(2+) channel.
authors.affiliation: Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, Rockville, Maryland 20850, USA.
authors.forename: Nobuko
authors.initials: N
authors.lastname: Hamasaki-Katagiri
authors.forename: James B
authors.initials: JB
authors.lastname: Ames
mesh_terms: D015153:Blotting, Western; D019703:Calcineurin / Q000502:physiology*; D065095:Calcineurin Inhibitors; D002118:Calcium / Q000494:pharmacology*; D002135:Calcium-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics / Q000502:physiology; D009154:Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000187:drug effects* / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D016559:Tacrolimus / Q000494:pharmacology
chemical_list: D065095:Calcineurin Inhibitors; D002135:Calcium-Binding Proteins; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; D029702:Schizosaccharomyces pombe Proteins; C405644:YAM8 protein, S pombe; D049452:Green Fluorescent Proteins; D019703:Calcineurin; D002118:Calcium; D016559:Tacrolimus