Plasma-membrane Cnh1 Na+/H+ antiporter regulates potassium homeostasis in Candida albicans.
The physiological role of Candida albicans Cnh1, a member of the Na+/H+ antiporter family, was characterized. Though CaCnh1p had broad substrate specificity and mediated efflux of at least four alkali metal cations upon heterologous expression in Saccharomyces cerevisiae, its presence in C. albicans cells was important especially for potassium homeostasis. In C. albicans, CaCnh1p tagged with GFP was localized in the plasma membrane of cells growing as both yeasts and hyphae. Deletion of CNH1 alleles did not affect tolerance to NaCl, LiCl or CsCl, but resulted in increased sensitivity to high external concentrations of KCl and RbCl. The potassium and rubidium tolerance of a cnh1 homozygous mutant was fully restored by reintegration of CNH1 into the genome. The higher sensitivity of the cnh1/cnh1 mutant to external KCl was caused by a lower K+ efflux from these cells. Together, the functional characterization of the CaCnh1 antiporter in C. albicans revealed that this antiporter plays a significant role in C. albicans physiology. It ensures potassium and rubidium tolerance and participates in the regulation of intracellular potassium content of C. albicans cells.
Kinclova-Zimmermannova
Olga
O
Department of Membrane Transport, Institute of Physiology AS CR, v.v.i., Videnska 1083, 142 20 Prague 4-Krc, Czech Republic.
Sychrová
Hana
H
Department of Membrane Transport, Institute of Physiology AS CR, v.v.i., Videnska 1083, 142 20 Prague 4-Krc, Czech Republic.
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002176:Candida albicans / Q000378:metabolism*; D002462:Cell Membrane / Q000737:chemistry; D002586:Cesium / Q000494:pharmacology; D002712:Chlorides / Q000494:pharmacology; D003001:Cloning, Molecular; D025141:Drug Resistance, Fungal; D005656:Fungal Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D015870:Gene Expression; D005816:Genetic Complementation Test; D006706:Homeostasis; D025301:Hyphae / Q000737:chemistry; D018021:Lithium Chloride / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D012413:Rubidium / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D017923:Sodium-Hydrogen Exchangers / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D015003:Yeasts / Q000737:chemistry
D000900:Anti-Bacterial Agents; C435129:CNH1 protein, Candida albicans; D002712:Chlorides; D005656:Fungal Proteins; D017923:Sodium-Hydrogen Exchangers; D002586:Cesium; D012965:Sodium Chloride; D011189:Potassium Chloride; D018021:Lithium Chloride; C028019:cesium chloride; D012413:Rubidium; C032710:rubidium chloride; D011188:Potassium