Membrane hyperpolarization and salt sensitivity induced by deletion of PMP3, a highly conserved small protein of yeast plasma membrane.
Yeast plasma membranes contain a small 55 amino acid hydrophobic polypeptide, Pmp3p, which has high sequence similarity to a novel family of plant polypeptides that are overexpressed under high salt concentration or low temperature treatment. The PMP3 gene is not essential under normal growth conditions. However, its deletion increases the plasma membrane potential and confers sensitivity to cytotoxic cations, such as Na(+) and hygromycin B. Interestingly, the disruption of PMP3 exacerbates the NaCl sensitivity phenotype of a mutant strain lacking the Pmr2p/Enap Na(+)-ATPases and the Nha1p Na(+)/H(+) antiporter, and suppresses the potassium dependency of a strain lacking the K(+) transporters, Trk1p and Trk2p. All these phenotypes could be reversed by the addition of high Ca(2+) concentration to the medium. These genetic interactions indicate that the major effect of the PMP3 deletion is a hyperpolarization of the plasma membrane potential that probably promotes a non-specific influx of monovalent cations. Expression of plant RCI2A in yeast could substitute for the loss of Pmp3p, indicating a common role for Pmp3p and the plant homologue.
Navarre
C
C
Unité de Biochimie Physiologique, Université Catholique de Louvain, Croix du Sud 2-20, 1348 Louvain-la-Neuve, Belgium.
Goffeau
A
A
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000502:physiology; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins; D002118:Calcium / Q000494:pharmacology; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology; D027682:Cation Transport Proteins; D002412:Cations / Q000494:pharmacology*; D019143:Evolution, Molecular; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D017353:Gene Deletion; D018390:Gene Targeting; D005816:Genetic Complementation Test; D006360:Heat-Shock Proteins / Q000235:genetics / Q000502:physiology; D006921:Hygromycin B / Q000494:pharmacology*; D017136:Ion Transport / Q000187:drug effects; D008564:Membrane Potentials / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology; D008969:Molecular Sequence Data; D009994:Osmolar Concentration; D010641:Phenotype; D010940:Plant Proteins / Q000737:chemistry; D011188:Potassium / Q000378:metabolism; D011510:Proteolipids / Q000235:genetics / Q000502:physiology*; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012965:Sodium Chloride / Q000494:pharmacology*; D017923:Sodium-Hydrogen Exchangers / Q000235:genetics / Q000502:physiology
D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D027682:Cation Transport Proteins; D002412:Cations; D005656:Fungal Proteins; D006360:Heat-Shock Proteins; D008565:Membrane Proteins; C410735:PMP3 protein, S cerevisiae; D010940:Plant Proteins; D011510:Proteolipids; D000644:Quaternary Ammonium Compounds; C108982:RCI2A protein, Arabidopsis; D029701:Saccharomyces cerevisiae Proteins; D017923:Sodium-Hydrogen Exchangers; C085258:TRK2 protein, S cerevisiae; C068664:TRK1 protein, S cerevisiae; D006921:Hygromycin B; D012965:Sodium Chloride; D000251:Adenosine Triphosphatases; C021838:sodium-translocating ATPase; C027917:tetramethylammonium; D011188:Potassium; D002118:Calcium