Proteomic analysis of experimentally induced azole resistance in Candida glabrata

• Published in: Journal of antimicrobial chemotherapy 2006-08, Vol.58 (2), p.434-438
• Main Authors: Rogers, P. David, Vermitsky, John-Paul, Edlind, Thomas D., Hilliard, George M.
• Format: Article
• Language: English
• Subjects: Antibiotics. Antiinfectious agents. Antiparasitic agents; Antifungal Agents - pharmacology; antifungals; Azoles - pharmacology; Bacteria; Biological and medical sciences; Candida glabrata; Candida glabrata - chemistry; Candida glabrata - drug effects; Candida glabrata - genetics; Drug resistance; Drug Resistance, Fungal; efflux pumps; Electrophoresis, Gel, Two-Dimensional; Electrophoresis, Polyacrylamide Gel; Fungal Proteins - analysis; Fungal Proteins - isolation & purification; Gene expression; Gene Expression Regulation, Fungal; lanosterol demethylase; Medical sciences; Mutation; Pharmacology. Drug treatments; Proteins; Proteome - analysis; Proteome - isolation & purification; Proteomics; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
• ISSN: 0305-7453; 1460-2091
• DOI: 10.1093/jac/dkl221

Objectives: The aim of the present study was to identify changes in the proteome of a laboratory-derived azole-resistant strain of Candida glabrata compared with its susceptible parent strain in an effort to identify proteins that are differentially expressed in association with azole resistance. Methods: Soluble and membrane protein fractions were isolated from mutant strain F15 (fluconazole MIC > 128 mg/L) and parent strain 66032 (fluconazole MIC = 16 mg/L) grown to mid-log phase. Soluble proteins were resolved by both two-dimensional (2D) and one-dimensional (1D) polyacrylamide gel electrophoresis (GE) whereas membrane proteins were resolved by 1D GE. Spots or bands representing differentially expressed proteins were identified by matrix-assisted desorption ionization-time of flight mass spectroscopy (MALDI-TOF MS) and peptide mass fingerprinting. Results: A total of 22 proteins were found to be more abundantly represented, and 3 proteins were found to be less abundantly represented, in strain F15 compared with strain 66032. These included up-regulation of the ATP-binding cassette transporter Cdr1p, the ergosterol biosynthesis enzyme Erg11p, proteins involved in glycolysis and glycerol metabolism, and proteins involved in the response to oxidative stress and cadmium exposure. Conclusions: In addition to transcriptional regulation of Cdr1p, this study identified the differential expression of several proteins that may contribute to azole resistance and suggests the possibility for a post-transcriptional mechanism for increased expression of Erg11p.