Localisation of Bgl2p upon antifungal drug treatment in Candida albicans

Several proteins are covalently bound to the cell wall glucan (glucan-associated proteins (GAPs)) in Candida albicans and different drugs may cause their modulation. Proteomic analysis is a suitable approach to study differential GAP patterns between control and drug-treated cells. Since antimycotics induce variation in GAP content, we investigated the effect of a sublethal dose of micafungin and observed a clear increase in Bgl2p, an enzyme with glucanosyltransferase activity, with respect to a general decrease in cell wall protein content. Immunoelectron microscopy using mouse antiserum confirmed this increase of Bgl2p on the outer cell wall but also revealed a dramatic increase in the immature Bgl2p isoform in the cytoplasm of drug-treated cells. Since this increased expression of Bgl2p is clearly dependent upon micafungin treatment, this enzyme appears to be one of the survival strategies of C. albicans and thus could be considered the molecular basis of antifungal resistance and also as a potential valuable candidate for future vaccine development.