This proposal describes our ongoing efforts to characterize the eight ALS (agglutinin-like sequence) genes of Candida albicans and determine the function of their encoded proteins. In the previous funding period, we generated a set of alsA/alsA mutant strains and evaluated their phenotype in assays for adhesion to host cells and molecules, and for their ability to cause damage in disease models. Data showed that several of the Als proteins contribute to adhesion of C. albicans to host surfaces and suggested other intriguing roles for the Als proteins. This competing continuation application includes experiments that utilize well-characterized Als proteins to define adhesive function at the molecular level and also pursues investigations to define the multifunctional nature of the Als family.
In Aim 1, the strong adhesive function of AlsSp is exploited to isolate the host cell proteins to which it binds;experiments to demonstrate the specificity of the interaction are also described. Surface plasmon resonance is utilized to further characterize these molecular interactions and random mutagenesis is used to define amino acids required for adhesive function. The focus of Aim 2 is ranking Als2p within the Als family for its relative contribution to adhesion to host cells and also to further define the role of Als2p and Alslp in regulation of C. albicans cell size.
Aim 3 expands on previous experiments that showed that mutagenesis of ALS5, ALS6 or ALS7 resulted in increased adhesion of C. albicans to host surfaces. Previous microarray analysis showed that deletion of these genes results in up-regulation of other C. albicans cell wall proteins that might have adhesive function.
Aim 4 makes use of our large collection of ALS-related strains and constructs to produce Als protein-specific monoclonal antibodies. These antibodies will be used to define Als protein localization on the surface of various C. albicans morphological forms, during cell mating, and on fungal cells from various animal disease models. We will also use the antibodies to support our conclusions about the role of Als proteins in C. albicans adhesion to host surfaces. Data from these studies are key to understanding Als adhesive interactions at the molecular level and understanding the breadth of function within the Als family.
|Cota, Ernesto; Hoyer, Lois L (2015) The Candida albicans agglutinin-like sequence family of adhesins: functional insights gained from structural analysis. Future Microbiol 10:1635-548|
|Lin, Jing; Oh, Soon-Hwan; Jones, Rhian et al. (2014) The peptide-binding cavity is essential for Als3-mediated adhesion of Candida albicans to human cells. J Biol Chem 289:18401-12|
|Coleman, David A; Oh, Soon-Hwan; Manfra-Maretta, Sandra L et al. (2012) A monoclonal antibody specific for Candida albicans Als4 demonstrates overlapping localization of Als family proteins on the fungal cell surface and highlights differences between Als localization in vitro and in vivo. FEMS Immunol Med Microbiol 64:321-33|
|Peters, Brian M; Jabra-Rizk, Mary Ann; O'May, Graeme A et al. (2012) Polymicrobial interactions: impact on pathogenesis and human disease. Clin Microbiol Rev 25:193-213|
|Murciano, Celia; Moyes, David L; Runglall, Manohursingh et al. (2012) Evaluation of the role of Candida albicans agglutinin-like sequence (Als) proteins in human oral epithelial cell interactions. PLoS One 7:e33362|
|Peters, Brian M; Ovchinnikova, Ekaterina S; Krom, Bastiaan P et al. (2012) Staphylococcus aureus adherence to Candida albicans hyphae is mediated by the hyphal adhesin Als3p. Microbiology 158:2975-2986|
|Zhao, Xiaomin; Oh, Soon-Hwan; Coleman, David A et al. (2011) ALS51, a newly discovered gene in the Candida albicans ALS family, created by intergenic recombination: analysis of the gene and protein, and implications for evolution of microbial gene families. FEMS Immunol Med Microbiol 61:245-57|
|Salgado, Paula S; Yan, Robert; Taylor, Jonathan D et al. (2011) Structural basis for the broad specificity to host-cell ligands by the pathogenic fungus Candida albicans. Proc Natl Acad Sci U S A 108:15775-9|
|Coleman, David A; Oh, Soon-Hwan; Zhao, Xiaomin et al. (2010) Heterogeneous distribution of Candida albicans cell-surface antigens demonstrated with an Als1-specific monoclonal antibody. Microbiology 156:3645-59|
|Beucher, Bertrand; Marot-Leblond, Agnès; Billaud-Nail, Sandrine et al. (2009) Recognition of Candida albicans Als3 by the germ tube-specific monoclonal antibody 3D9.3. FEMS Immunol Med Microbiol 55:314-23|
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