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An endocytic mechanism for haemoglobin‐iron acquisition in Candida albicans
Author(s) -
Weissman Ziva,
Shemer Revital,
Conibear Elizabeth,
Kornitzer Daniel
Publication year - 2008
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2008.06277.x
Subject(s) - candida albicans , endocytic cycle , biology , endocytosis , mutant , vacuole , saccharomyces cerevisiae , corpus albicans , biochemistry , escrt , fungal protein , microbiology and biotechnology , transferrin , extracellular , yeast , endosome , intracellular , receptor , gene , cytoplasm
Summary The fungal pathogen Candida albicans is able to utilize haemin and haemoglobin as iron sources. Haem‐iron utilization is facilitated by Rbt5, an extracellular, glycosylphophatidylinositol (GPI)‐anchored, haemin‐ and haemoglobin‐binding protein. Here, we show that Rbt5 and its close homologue Rbt51 are short‐lived plasma membrane proteins, degradation of which depends on vacuolar activity. Rbt5 facilitates the rapid endocytosis of haemoglobin into the C. albicans vacuole. We relied on recapitulation of the Rbt51‐dependent haem‐iron utilization in Saccharomyces cerevisiae to identify mutants defective in haemoglobin utilization. Homologues of representative mutants in S. cerevisiae were deleted in C. albicans and tested for haemoglobin‐iron utilization and haemoglobin uptake. These mutants define a novel endocytosis‐mediated haemoglobin utilization mechanism that depends on acidification of the lumen of the late secretory pathway, on a type I myosin and on the activity of the ESCRT pathway.