title: Regulation of Trk-dependent potassium transport by the calcineurin pathway involves the Hal5 kinase.
abstract: The phosphatase calcineurin and the kinases Hal4/Hal5 regulate high-affinity potassium uptake in Saccharomyces cerevisiae through the Trk1 transporter. We demonstrate that calcineurin is necessary for high-affinity potassium uptake even in the absence of Na(+) stress. HAL5 expression is induced in response to stress in a calcineurin-dependent manner through a newly identified functional CDRE (nt -195/-189). Lack of calcineurin decreases Hal5 protein levels, although with little effect on Trk1 amounts. However, the growth defect of cnb1 cells at K(+)-limiting conditions can be rescued in part by overexpression of HAL5, and this mutation further aggravates the potassium requirements of a hal4 strain. This suggests that the control exerted by calcineurin on Hal5 expression may be biologically relevant for Trk1 regulation.
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Universitat Autónoma de Barcelona, Barcelona, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Casado
authors.forename: Lynne
authors.initials: L
authors.lastname: Yenush
authors.forename: Carmen
authors.initials: C
authors.lastname: Melero
authors.forename: María del Carmen
authors.initials: Mdel C
authors.lastname: Ruiz
authors.forename: Raquel
authors.initials: R
authors.lastname: Serrano
authors.forename: Jorge
authors.initials: J
authors.lastname: Pérez-Valle
authors.forename: Joaquín
authors.initials: J
authors.lastname: Ariño
authors.forename: José
authors.initials: J
authors.lastname: Ramos
mesh_terms: D001692:Biological Transport / Q000235:genetics; D019703:Calcineurin / Q000378:metabolism*; D017136:Ion Transport / Q000235:genetics; D007477:Ions / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism*; D009154:Mutation; D011188:Potassium / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
chemical_list: D007477:Ions; D026901:Membrane Transport Proteins; D029701:Saccharomyces cerevisiae Proteins; D011494:Protein Kinases; C522341:Hal5 protein, S cerevisiae; D019703:Calcineurin; D011188:Potassium