| Title | Saccharomyces cerevisiae Can Secrete Sapp1p Proteinase of Candida parapsilosis But Cannot Use It for Efficient Nitrogen Acquisition |
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| Author | Zuzana Vinterová1, Václava Bauerová1, Jiří Dostál1, Hana Sychrová2, Olga Hrušková-Heidingsfeldová1, and Iva Pichová1* |
| Address | 1Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic, v.v.i., Gilead & IOCB Research Centre, Flemingovo náměstí 2, 166 10 Prague 6, Czech Republic, 2Department of Membrane Transport, Institute of Physiology Academy of Sciences of the Czech Republic, v.v.i., Vídeňská 1083, 142 20 Prague 4, Czech Republic |
| Bibliography | Journal of Microbiology, 51(3),336-344, 2013, |
| DOI | 10.1007/s12275-013-2422-4 |
| Key Words | Candida parapsilosis, Saccharomyces cerevisiae, secreted aspartic proteinase, SAPP1, nitrogen metabolism |
| Abstract | Secreted aspartic proteinase Sapp1p of Candida parapsilosis represents one of the factors contributing to the pathogenicity of the fungus. The proteinase is synthesized as an inactive pre-pro-enzyme, but only processed Sapp1p is secreted into extracellular space. We constructed a plasmid containing the SAPP1 coding sequence under control of the ScGAL1 promoter and used it for proteinase expression in a Saccharomyces cerevisiae kex2Δ mutant. Because Sapp1p maturation depends on cleavage by Kex2p proteinase, the kex2Δ mutant secreted only the pro-form of Sapp1p. Characterization of this secreted proteinase form revealed that the Sapp1p signal peptide consists of 23 amino acids. Additionally, we prepared a plasmid with the SAPP1 coding sequence under control of its authentic CpSAPP1 promoter, which contains two GATAA motifs. While in C. parapsilosis SAPP1 expression is repressed by good low molecular weight nitrogen sources (e.g., ammonium ions), S. cerevisiae cells harboring this plasmid secreted a low concentration of active proteinase regardless of the type of nitrogen source used. Quantitative real-time PCR analysis of a set of genes related to nitrogen metabolism and uptake (GAT1, GLN3, STP2, GAP1, OPT1, and PTR2) obtained from S. cerevisiae cells transformed with either plasmid encoding SAPP1 under control of its own promoter or empty vector and cultivated in media containing various nitrogen sources also suggested that SAPP1 expression can be connected with the S. cerevisiae regulatory network. However, this regulation occurs in a different manner than in C. parapsilosis. |