title: Characterization of the energy-dependent, mating factor-activated Ca2+ influx in Saccharomyces cerevisiae.
abstract: The yeast mating pheromones, a and alpha factors, bind to specific G protein-coupled receptors in haploid cells and bring about both growth arrest in the early G1 phase of the cell cycle and differentiation into mating capable cells. This induces an increase in Ca2+ influx leading to elevated intracellular calcium concentrations, which has been shown to be essential for subsequent downstream events and the mating process itself [1]. We have characterized the alpha factor induced increase in cellular Ca2+ in wild type S. cerevisiae and in the temperature-sensitive cell division cycle mutants cdc7 and cdc28 which are growth-arrested at the G0-G1 border at the nonpermissive temperature. We observed a 2-4 fold increase in the initial velocity of Ca2+ influx in alpha factor-treated wild-type cells and in cdc7 and cdc28 cells grown at the nonpermissive temperature. Calcium influx was energy dependent, inhibited by membrane depolarization and slightly increased by hyperpolarization. Furthermore, Ca2+ influx was sensitive to both divalent and trivalent cations, but was unaffected by nifedipine and verapamil. These data demonstrate that budding yeast possesses a regulated Ca2+ transport mechanism, the activation of which is dependent upon exit out of the cell cycle and growth cessation. This transport mechanism has many similarities to that observed in mitogen-stimulated mammalian cells.
authors.affiliation: Department of Pediatrics (Hematology/Oncology), Tufts University School of Medicine, Boston, Massachusetts.
authors.forename: K R
authors.initials: KR
authors.lastname: Prasad
authors.forename: P M
authors.initials: PM
authors.lastname: Rosoff
mesh_terms: D019297:2,4-Dinitrophenol; D001693:Biological Transport, Active / Q000187:drug effects; D017489:CDC28 Protein Kinase, S cerevisiae / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000187:drug effects; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002412:Cations / Q000494:pharmacology; D018797:Cell Cycle Proteins; D002454:Cell Differentiation / Q000187:drug effects; D004140:Dinitrophenols / Q000494:pharmacology; D005656:Fungal Proteins / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism; D007399:Interphase / Q000187:drug effects; D015640:Ion Channel Gating / Q000187:drug effects; D000072235:Mating Factor; D008564:Membrane Potentials; D009543:Nifedipine / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology*; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction / Q000187:drug effects; D014634:Valinomycin / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
chemical_list: D015220:Calcium Channels; D002412:Cations; D018797:Cell Cycle Proteins; D004140:Dinitrophenols; D005656:Fungal Proteins; D010455:Peptides; D029701:Saccharomyces cerevisiae Proteins; D014634:Valinomycin; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D000072235:Mating Factor; D014700:Verapamil; D011494:Protein Kinases; C489404:CDC7 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; D017489:CDC28 Protein Kinase, S cerevisiae; D019204:GTP-Binding Proteins; D009543:Nifedipine; D019297:2,4-Dinitrophenol; D002118:Calcium