The Na+,K+/H+ -antiporter Nha1 influences the plasma membrane potential of Saccharomyces cerevisiae.
There are three different sodium transport systems (Ena1-4p, Nha1p, Nhx1p) in Saccharomyces cerevisiae. The effect of their absence on the tolerance to alkali-metal cations and on the membrane potential was studied. All three sodium transporters were found to participate in the maintenance of Na+, Li+, K+ and Cs+ homeostasis. Measurements of the distribution of a fluorescent potentiometric probe (diS-C3(3) assay) in cell suspensions showed that the lack of all three transporters depolarizes the plasma membrane. The overexpression of the Na+,K+/H+ antiporter Nha1 resulted in the hyperpolarization of the plasma membrane and consequently increased the sensitivity to Cs+, Tl+ and hygromycin B. This is the first evidence that the activity of a Na+,K+/H+ antiporter could play a role in the homeostatic regulation of the plasma membrane potential in yeast cells.
Kinclova-Zimmermannova
Olga
O
Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Gaskova
Dana
D
Sychrova
Hana
H
D027682:Cation Transport Proteins / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D008564:Membrane Potentials; D008565:Membrane Proteins / Q000502:physiology*; D011188:Potassium / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*; D012964:Sodium / Q000378:metabolism; D017923:Sodium-Hydrogen Exchangers / Q000502:physiology*
D027682:Cation Transport Proteins; D008565:Membrane Proteins; C000631624:NHA1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D017923:Sodium-Hydrogen Exchangers; D012964:Sodium; D011188:Potassium