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Proteomic analysis of cytoplasmic extracts from a
mutant of Candida glabrata and its
parent strain.
Loureiro y Penha, C.V. 1; Kubitschek-Barreira, P.H.1; Larcher, G.2, Perales, J.3; León, I.R.3; Lopes-Bezerra, L.M.3 and Bouchara, J.F.2
1Laboratório de Micologia e Proteômica, IBRAG, Universidade do Estado do Rio de Janeiro (UERJ), Brasil; 2Host-Parasite Interaction Study Group, Angers University Hospital, France; 3Laboratório de Toxinologia, Fiocruz, RJ, Brasil. E-mail: carla@uerj.br
Over the past two decades, the incidence of infections due to Candida glabrata has increased markedly, probably in relation with its low intrinsic susceptibility to azole antifungals. The sequencing of C. glabrata
genome as well as recent refinements in protein resolution and
identification techniques has enhanced the application of proteomics
for the study of this yeast species. Several proteomic studies have
been performed in the context of virulence, drug response and
antifungal resistance in Candida albicans. Previously, it has been shown that petite mutations lead in C. glabrata
to an acquired resistance to azole drugs, due to the overexpression of
nuclear genes encoding some efflux pumps. However, due to the
cross-talk between nucleus and mitochondria, the expression of other
nuclear genes may also be affected by these mutations. In the present
work, cytoplasmic extracts from a fluconazole resistant strain, an
ethidium bromide-induced mutant of C. glabrata, and
from its azole-susceptible parent isolate were compared by
two-dimensional polyacrylamide gel electrophoresis. Protein
identification was carried out by peptide mass fingerprinting or
sequence tagging using MALDI-TOF or MALDI-TOF/TOF mass spectrometer. A
total of 70 spots gels from each strain were excised from 2-D gels and
analyzed. In the wild-type strain, this resulted in the identification
of 46 proteins involved in metabolism, 13 involved in transcription and
protein synthesis, and fate metabolism, 4 in cell rescue, virulence and
defense, and 7 proteins of unknown function. In the petite mutant, we
had identified 42 proteins involved in metabolism, 10 in transcription,
protein synthesis, and fate, 2 involved in cell rescue, virulence and
defense, and 16 proteins of unknown function. Among these proteins, it
seems that 4 were overexpressed in the mutant strain and 5 in the
parent isolate. These results may help to a better understanding of the nuclear response to impairment of mitochondrial function. In
addition, this study may constitute an important milestone for future
applications of this approach in investigations about azole resistance
in C. glabrata. Supported by Rede Proteômica do Rio de Janeiro/Faperj and CNPq
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