Proteomic analysis of experimentally induced azole resistance in Candida glabrata.
OBJECTIVE
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.
Rogers
P David
PD
Department of Pharmacy, College of Pharmacy, University of Tennessee Health Science Center Memphis, TN 38163, USA. drogers@utmem.edu
Vermitsky
John-Paul
JP
Edlind
Thomas D
TD
Hilliard
George M
GM
D000935:Antifungal Agents / Q000494:pharmacology*; D001393:Azoles / Q000494:pharmacology*; D041221:Candida glabrata / Q000737:chemistry* / Q000187:drug effects* / Q000235:genetics; D025141:Drug Resistance, Fungal; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D005656:Fungal Proteins / Q000032:analysis* / Q000302:isolation & purification; D015966:Gene Expression Regulation, Fungal; D009154:Mutation; D020543:Proteome / Q000032:analysis* / Q000302:isolation & purification; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D000935:Antifungal Agents; D001393:Azoles; D005656:Fungal Proteins; D020543:Proteome