title: Sexual pheromone modulates the frequency of cytosolic Ca2+bursts inSaccharomyces cerevisiae.
abstract: Transient and highly regulated elevations of cytosolic Ca2+control a variety of cellular processes. Bulk measurements using radioactive Ca2+and the luminescent sensor aequorin have shown that in response to pheromone, budding yeast cells undergo a rise of cytosolic Ca2+that is mediated by two import systems composed of the Mid1-Cch1-Ecm7 protein complex and the Fig1 protein. Although this response has been widely studied, there is no treatment of Ca2+dynamics at the single-cell level. Here, using protein calcium indicators, we show that both vegetative and pheromone-treated yeast cells exhibit discrete and asynchronous Ca2+bursts. Most bursts reach maximal amplitude in 1-10 s, range between 7 and 30 s, and decay in a way that fits a single-exponential model. In vegetative cells, bursts are scarce but preferentially occur when cells are transitioning G1 and S phases. On pheromone presence, Ca2+burst occurrence increases dramatically, persisting during cell growth polarization. Pheromone concentration modulates burst frequency in a mechanism that depends on Mid1, Fig1, and a third, unidentified, import system. We also show that the calcineurin-responsive transcription factor Crz1 undergoes nuclear localization bursts during the pheromone response.
authors.affiliation: Laboratorio de Biología Celular de Membranas, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay.
authors.forename: Natalia
authors.initials: N
authors.lastname: Carbó
authors.affiliation: Laboratorio de Biología Celular de Membranas, Instituto de Investigaciones Biotecnológicas, Universidad de San Martin, San Martin 1650CPZ, Argentina.|Departamento de Física and IFIBA, CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina.
authors.forename: Nahuel
authors.initials: N
authors.lastname: Tarkowski
authors.affiliation: Departamento de Física and IFIBA, CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina.
authors.forename: Emiliano Perez
authors.initials: EP
authors.lastname: Ipiña
authors.affiliation: Departamento de Física and IFIBA, CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina.
authors.forename: Silvina Ponce
authors.initials: SP
authors.lastname: Dawson
authors.affiliation: Laboratorio de Biología Celular de Membranas, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay paguilar@iib.unsam.edu.ar.|Laboratorio de Biología Celular de Membranas, Instituto de Investigaciones Biotecnológicas, Universidad de San Martin, San Martin 1650CPZ, Argentina.
authors.forename: Pablo S
authors.initials: PS
authors.lastname: Aguilar
mesh_terms: D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D010675:Pheromones / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D012724:Sex Attractants / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D015220:Calcium Channels; C000592000:Fig1 protein, S cerevisiae; C090463:MID1 protein, S cerevisiae; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D010675:Pheromones; D029701:Saccharomyces cerevisiae Proteins; D012724:Sex Attractants; D002118:Calcium