Regulation of salt tolerance by Torulaspora delbrueckii calcineurin target Crz1p.
Recently, the academic interest in the yeast Torulaspora delbrueckii has increased notably due to its high resistance to several types of stress, including salt and osmotic imbalance. However, the molecular mechanisms underlying these unusual properties are poorly understood. In Saccharomyces cerevisiae, the high-salt response is mediated by calcineurin, a conserved Ca(2+)/calmodulin-modulated protein phosphatase that regulates the transcriptional factor Crz1p. Here, we cloned the T. delbrueckii TdCRZ1 gene, which encodes a putative zinc finger transcription factor homologue to Crz1p. Consistent with this, overexpression of TdCRZ1 enhanced the salt tolerance of S. cerevisiae wild-type cells and suppressed the sensitivity phenotype of cnb1Delta and crz1Delta mutants to monovalent and divalent cations. However, T. delbrueckii cells lacking TdCrz1p showed phenotypes distinct from those previously observed in S. cerevisiae crz1Delta mutants. Quite remarkably, Tdcrz1-null cells were insensitive to high Na(+) and were more Li(+) tolerant than wild-type cells. Clearly, TdCrz1p was not required for the salt-induced transcriptional activation of the TdENA1 gene, encoding a putative P-type ATPase homologue to the main S. cerevisiae Na(+) pump ENA1. Furthermore, T. delbrueckii cells were insensitive to the immunosuppressive agents FK506 and cyclosporine A, both in the presence and in the absence of NaCl. Signaling through the calcineurin/Crz1 pathway appeared to be essential only on high-Ca(2+)/Mn(2+) media. Hence, T. delbrueckii and S. cerevisiae differ in the regulatory circuits and mechanisms that drive the adaptive response to salt stress.
Hernandez-Lopez
Maria Jose
MJ
Department of Biotechnology, Instituto de Agroquímica y Tecnología de los Alimentos, Consejo Superior de Investigaciones Científicas, P.O. Box 73, E-46100 Burjassot, Valencia, Spain.
Panadero
Joaquin
J
Prieto
Jose Antonio
JA
Randez-Gil
Francisca
F
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001483:Base Sequence; D019703:Calcineurin / Q000235:genetics / Q000378:metabolism*; D017124:Conserved Sequence; D004271:DNA, Fungal / Q000032:analysis; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D009154:Mutation; D017434:Protein Structure, Tertiary; D004718:Saccharomycetales / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology*; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D016335:Zinc Fingers; D001616:beta-Galactosidase / Q000032:analysis / Q000378:metabolism
D004271:DNA, Fungal; D015534:Trans-Activators; D014157:Transcription Factors; D012965:Sodium Chloride; D012964:Sodium; D019703:Calcineurin; D001616:beta-Galactosidase; D000251:Adenosine Triphosphatases