Pathogenesis of Candida albicans (CA) and other Candida species involves direct contact of the organism's cell surface with host tissues. Little is known about how Candida species surface macromolecules are modified during initiation of pathogenesis and establishment of infection. However, it has been shown that the cell surface of C. albicans varies in surface hydrophobicity status and that cell surface hydrophobicity (CSH) enhances pathogenicity of C. albicans. Recent studies suggest that CSH status of C. albicans is determined by cell wall protein mannosylation. Biochemical, biophysical, and immunologic studies lead us to propose that modification of the beta-1,2-phosphomannosyl group critically influences exposure of surface hydrophobic proteins (and therefore pathogenesis). In this project, the group will firmly establish the importance of the beta-1,2-phosphomannosyl group in conferring cell surface hydrophobicity. To do so, they will perform the following: 1) test by biochemical means the hypothesis that alteration of the beta-1,2-phosphomannosyl (beta-1,2ManP) group, not necessarily other mannosyl regions, determines CSH; 2) identify and clone the initial synthetic genes for beta-1,2ManP. At least two critical enzymatic steps are involved in synthesis of the beta-1,2ManP group. The first is a phosphomannosyl transferase and the second is a beta-1,2-mannosyltransferase (beta1,2-ManTase); 3) determine the role of the genes in conferring hydrophilicity by phenotypic characterization of the phosphomannosyl transferase and beta-1,2-mannosyltransferase; and 4) establish the general regulation of expression during growth and morphogenesis. From these experiments the PI will demonstrate the critical role of phosphomannosyl transferase and beta1,2-ManTase in determining CSH of C. albicans and influencing cell adhesion. The long-term goal of this research is to dissect the mechanisms of mannosylation of C. albicans cell wall proteins during pathogenesis and determine which ones provide the best targets for anti-Candida species therapy. Regardless of whether expression of the genes is involved in CSH status, elucidation of the genetic mechanism of expression of the beta1,-2ManP group will influence vaccine studies and contribute to the understanding of cell wall protein mannosylation events in pathogenesis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI043997-02
Application #
6373994
Study Section
Bacteriology and Mycology Subcommittee 2 (BM)
Program Officer
Duncan, Rory A
Project Start
2000-08-01
Project End
2005-07-31
Budget Start
2001-08-01
Budget End
2002-07-31
Support Year
2
Fiscal Year
2001
Total Cost
$357,033
Indirect Cost
Name
University of Virginia
Department
Pathology
Type
Schools of Medicine
DUNS #
001910777
City
Charlottesville
State
VA
Country
United States
Zip Code
22904
Hazen, Kevin C; Singleton, David R; Masuoka, James (2007) Influence of outer region mannosylphosphorylation on N-glycan formation by Candida albicans: normal acid-stable N-glycan formation requires acid-labile mannosylphosphate addition. Glycobiology 17:1052-60
Masuoka, James; Hazen, Kevin C (2006) Effect of monosaccharide composition, glycosidic linkage position and anomericity on the electrophoretic mobility of labeled oligosaccharides. Electrophoresis 27:365-72
Singleton, David R; Fidel Jr, Paul L; Wozniak, Karen L et al. (2005) Contribution of cell surface hydrophobicity protein 1 (Csh1p) to virulence of hydrophobic Candida albicans serotype A cells. FEMS Microbiol Lett 244:373-7
Singleton, David R; Masuoka, James; Hazen, Kevin C (2005) Surface hydrophobicity changes of two Candida albicans serotype B mnn4delta mutants. Eukaryot Cell 4:639-48
Hazen, Kevin C (2004) Relationship between expression of cell surface hydrophobicity protein 1 (CSH1p) and surface hydrophobicity properties of Candida dubliniensis. Curr Microbiol 48:447-51
Masuoka, James; Hazen, Kevin C (2004) Cell wall mannan and cell surface hydrophobicity in Candida albicans serotype A and B strains. Infect Immun 72:6230-6
Masuoka, James (2004) Surface glycans of Candida albicans and other pathogenic fungi: physiological roles, clinical uses, and experimental challenges. Clin Microbiol Rev 17:281-310
Singleton, David R; Hazen, Kevin C (2004) Differential surface localization and temperature-dependent expression of the Candida albicans CSH1 protein. Microbiology 150:285-92
Masuoka, James; Guthrie, Lori N; Hazen, Kevin C (2002) Complications in cell-surface labelling by biotinylation of Candida albicans due to avidin conjugate binding to cell-wall proteins. Microbiology 148:1073-9
Singleton, D R; Masuoka, J; Hazen, K C (2001) Cloning and analysis of a Candida albicans gene that affects cell surface hydrophobicity. J Bacteriol 183:3582-8

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