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Assay for Adhesion and Agar Invasion in S. cerevisiae
Published on: November 8, 2006
Two aspartic proteinases secreted by the pathogenic yeast Candida parapsilosis differ in expression pattern and
Olga Hrusková-Heidingsfeldová1, Jirí Dostál, Filip Majer
1Gilead Sciences Research Center, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo námĕstí 2, CZ-166 10 Prague 6, Czech Republic. olga-hh@uochb.cas.cz
Biological Chemistry
|January 27, 2009
Summary
Secreted aspartic proteinases (Sap) in Candida parapsilosis show differential gene expression based on nitrogen sources. Sapp1p is highly expressed when protein is the sole nitrogen source, unlike Sapp2p.
Area of Science:
- Mycology
- Molecular Biology
- Biochemistry
Background:
- Secreted aspartic proteinases (Sap) are virulence factors in pathogenic fungi like Candida species.
- Candida parapsilosis encodes three Sap enzymes: Sap1p, Sap2p, and Sap3p.
Purpose of the Study:
- To investigate the differential expression and activity of Sap1p and Sap2p in Candida parapsilosis.
- To understand the role of nitrogen sources in regulating Sap enzyme production and function.
Main Methods:
- Analysis of SAPP1 and SAPP2 gene expression under various nitrogen conditions.
- Quantification of Sapp1p and Sapp2p protein secretion.
- Enzymological characterization of purified Sapp1p and Sapp2p.
- Structural analysis using homology modeling.
Main Results:
- SAPP2 transcript is constitutively expressed, while SAPP1 expression is induced by exogenous protein as the sole nitrogen source.
- Induced Sapp1p levels are significantly higher (at least one order of magnitude) than Sapp2p levels.
- Sapp1p exhibits broader substrate specificity and higher catalytic activity compared to Sapp2p.
- Structural differences in homology models correlate with observed functional variations.
Conclusions:
- Candida parapsilosis secretes low levels of Sapp2p with limited activity under most conditions.
- High-level secretion of catalytically efficient Sapp1p is triggered by the presence of protein as a nitrogen source.
- Differential regulation of Sap enzymes impacts fungal virulence and nutrient acquisition strategies.
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