Yeast wall protein 1 of Candida albicans

1 Department of Microbiology, Montana State University, Bozeman, MT, USA 2 Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA 3 Department of Microbiology, Columbia University, New York, NY, USA 4 Department of Microbiology, University of Minnesota, Minneapolis, MN, USA 5 Research Institute for Children and Louisiana State University Health Sciences Center, Children's Hospital, New Orleans, LA, USA Correspondence Bruce L. Granger bgranger{at}montana.edu Yeast wall protein 1 (Ywp1, also called Pga24) of Candida albicans is predicted to be a 533 aa polypeptide with an N-terminal secretion signal, a C-terminal glycosylphosphatidylinositol anchor signal and a central region rich in serine and threonine. In yeast cultures, Ywp1p appeared to be linked covalently to glucans of the wall matrix, but, as cultures approached stationary phase, Ywp1p accumulated in the medium and was extractable from cells with disulfide-reducing agents. An 11 kDa propeptide of Ywp1p was also present in these soluble fractions; it possessed the sole N -glycan of Ywp1p and served as a useful marker for Ywp1p. DNA vaccines encoding all or part of Ywp1p generated analytically useful antisera in mice, but did not increase survival times for disseminated candidiasis. Replacement of the coding sequence of YWP1 with the fluorescent reporter GFP revealed that expression of YWP1 is greatest during yeast exponential-phase growth, but downregulated in stationary phase and upon filamentation. Expression was upregulated when the extracellular phosphate concentration was low. Disruption by homologous recombination of both YWP1 alleles resulted in no obvious change in growth, morphology or virulence, but the Ywp1p-deficient blastoconidia exhibited increased adhesiveness and biofilm formation, suggesting that Ywp1p may promote dispersal of yeast forms of C. albicans . Abbreviations: CV, crystal violet; GFP, green fluorescent protein; GPI, glycosylphosphatidylinositol; HMM, high molecular mass; IEF, isoelectric focusing; MS, mass spectrometry; PNGase F, peptide N -glycanase F The GenBank/EMBL/DDBJ accession numbers for the sequences reported in this paper are AY656807 , AY656808 , AY660719 and AY661302 . Supplementary material is available with the online version of this paper.