Biogenesis of Candida albicans Can1 permease expressed in Saccharomyces cerevisiae.

The Candida albicans CAN1 gene, encoding a high-affinity permease for arginine, lysine and histidine, was tagged at its C-terminus with a c-myc epitope and introduced into strains of Saccharomyces cerevisiae lacking basic amino acid permeases. The expression levels of Ca-Can1p were influenced by the available nitrogen source, being almost negligible when cells were grown in the presence of ammonia. Ca-Can1p was shown to follow the secretory pathway in S. cerevisiae. Ca-Can1p activity was not detected in a secretion-defective sec1-1 mutant grown at a non-permissive temperature. Shr3p, an ER protein that participates in the biogenesis of amino acid permeases was also required for the functional expression of Ca-Can1p. The shr3 mutation does not affect the affinity for substrate but does decrease the number of Can1p molecules reaching the plasma membrane.