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CaRch1p does not functionally interact with the high‐affinity Ca 2+ influx system (HACS) of Candida albicans
Author(s) -
Alber Joerg,
Jiang Linghuo,
Geyer Joachim
Publication year - 2013
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/yea.2981
Subject(s) - biology , candida albicans , microbiology and biotechnology
The plasma membrane protein CaRch1p of Candida albicans , homologous to the human solute carrier protein SLC10A7, is involved in the regulation of calcium homeostasis. C . albicans cells lacking CaRCH1 are hypersensitive to high extracellular Ca 2+ concentrations and show increased tolerance to ketoconazole (KCZ). We assume a higher basal Ca 2+ influx in the rch1/rch1 mutant strain at low extracellular Ca 2+ concentrations, which is not detrimental to C. albicans cells but may be sufficient to activate calcineurin, finally resulting in an increased tolerance to KCZ. However, at 8 µg/ml KCZ plus 3 m m Ca 2+ the rch1/rch1 mutant and the wild‐type strains showed identical growth. By further increasing the Ca 2+ concentration to 30 m m , this phenotype was completely reversed and the rch1/rch1 mutant strain became extremely sensitive to 8 µg/ml KCZ, probably due to synergistic toxic effects of Ca 2+ and KCZ under these conditions. Furthermore, we aimed to clarify whether CaRch1p interacts with the Cch1p component of the voltage‐gated calcium influx channel Cch1p/Mid1p in C. albicans cells. As disruption of the two alleles of CCH1 in the rch1 / rch1 mutant strain did not alter its hypersensitivity to high extracellular Ca 2+ , and as this phenotype was completely abolished by low amounts of Mg 2+ in the rch1/rch1 mutant as well as in the cch1/cch1 rch1/rch1 double mutant, we conclude that CaRch1p is a functional component of the low‐affinity calcium uptake system (LACS) system and does not functionally interact with Cch1p. Copyright © 2013 John Wiley & Sons, Ltd.