The Acid Phosphatase of Saccharomyces Cerevisiae: A Model to Study Wall Protein Expression

Abstract

Reports of the incidence of invasive mycosis have increased in recent years, particularly in immunosuppressed patients. Consequently, interest in the mechanisms involved in the pathogenicity of fungi is growing. The fungal cell wall is the key site of interaction between the fungus and the parasitized host. The fungal cell wall is comprised of polysaccharides and glycoproteins. Both types of components represent the major antigens expressed during mycosis and are essential markers for the diagnosis of fungal infections. Molecular biology of the protein secretion present new ways for understanding and analysing the cell wall antigens synthesis and the virulence of pathogenic fungi. Until now, the principal data on protein secretion in fungi have been obtained in fundamental research and in biotechnology with the brewer yeast, Saccharomyces cerevisiae. A unique collection of thermosensitive mutants — the sec mutants — was isolated 10 years ago in S. cerevisiae (Novick et al., 1980). These mutants contain conditionnally lethal mutations, that block secretion at the restrictive temperature, causing accumulation of the proteins at specific stages in their intracellular route. The use of these mutants allowed the demonstration that the secretion pathway in S. cerevisiae is very similar to that of higher eucaryotic cells (Novick et al., 1981). Secretory proteins enter the endoplasmic reticulum (ER), where the initial Ateps of glycosylation occur. Proteins are then transferred to a Golgi-like structure, where further glycosylation proceeds. Fully glycosylated proteins are then packaged into vesicles that are transported to the bud where they fuse with the plasma membrane.KeywordsSignal PeptideBrewer YeastAPase ActivityPH05 GeneCell BioIThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.