RT Journal Article
T1 Ectopic Potassium Uptake in trk1 trk2 Mutants ofSaccharomyces cerevisiae Correlates with a Highly Hyperpolarized Membrane Potential
A1 Madrid González, Ricardo
A1 Gómez, Marı́a
A1 Ramos Ruiz, José
A1 Rodrı́guez-Navarro, Alonso
AB Null trk1 trk2 mutants of Saccharomyces cerevisiae exhibit a low-affinity uptake of K1 and Rb1. We show that this low-affinity Rb1 uptake is mediated by several independent transporters, and that trk1D cells and especially trk1D trk2D cells are highly hyperpolarized. Differences in the membrane potentials were assessed for sensitivity to hygromycin B and by flow cytometric analyses of cellular DiOC6(3) fluorescence. On the basis of the latter analyses, it is proposed that Trk1p and Trk2p are involved in the control of the membrane potential, preventing excessive hyperpolarizations. K1 starvation and nitrogen starvation hyperpolarize both TRK1 TRK2 and trk1D trk2D cells, thus suggesting that other proteins, in addition to Trk1p and Trk2p, participate in the control of the membrane potential. The HAK1 K1 transporter from Schwanniomyces occidentalis suppresses the K1-defective transport of trk1D trk2D cells but not the high hyperpolarization, and the HKT1 K1 transporter from wheat suppresses both defects, in the presence of Na1. We discuss the mechanism involved in the control of the membrane potential by Trk1p and Trk2p and the causal relationship between the high membrane potential (negative inside) of trk1D trk2D cells and its ectopic transport of alkali cations.
PB American Society for Biochemistry and Molecular Biolog
SN 0021-9258
YR 1998
FD 1998
LK https://hdl.handle.net/20.500.14352/98136
UL https://hdl.handle.net/20.500.14352/98136
LA eng
NO Madrid, Ricardo, et al. «Ectopic Potassium Uptake in Trk1 Trk2 Mutants ofSaccharomyces Cerevisiae Correlates with a Highly Hyperpolarized Membrane Potential». Journal of Biological Chemistry, vol. 273, n.o 24, junio de 1998, pp. 14838-44. https://doi.org/10.1074/jbc.273.24.14838.
DS Docta Complutense
RD 5 abr 2025