Candida albicans Potassium Transporters

Abstract

Potassium is basic for life. All living organisms require high amounts of intracellular potassium, which fulfils multiple functions. To reach efficient potassium homeostasis, eukaryotic cells have developed a complex and tightly regulated system of transporters present both in the plasma membrane and in the membranes of internal organelles that allow correct intracellular potassium content and distribution. We review the information available on the pathogenic yeast Candida albicans. While some of the plasma membrane potassium transporters are relatively well known and experimental data about their nature, function or regulation have been published, in the case of most of the transporters present in intracellular membranes, their existence and even function have just been deduced because of their homology with those present in other yeasts, such as Saccharomyces cerevisiae. Finally, we analyse the possible links between pathogenicity and potassium homeostasis. We comment on the possibility of using some of these transporters as tentative targets in the search for new antifungal drugs.

Keywords: Candida albicans; organelles; pathogenicity; plasma membrane; potassium; potassium homeostasis; potassium transporters.

Figure 1

Putative potassium transporters identified in C. albicans. The ATPase encoded by PMA1 extrudes protons and creates a membrane potential that drives K⁺ movements. The function of the KHE system and Kch1 transporter has not been definitively determined in either S. cerevisiae or C. albicans.