Identification of potential cell-surface proteins in Candida albicans and investigation of the role of a putative cell-surface glycosidase in adhesion and virulence
Identification of potential cell-surface proteins in Candida albicans and investigation of the role of a putative cell-surface glycosidase in adhesion and virulence
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作者：
Alberti-Segui, C;Morales, AJ;Rogers, B
细胞表面蛋白是开发新型抗真菌药物的有吸引力的靶标，因为它们比细胞内靶标更容易被药物获取。通过计算生物学方法，我们鉴定了白色念珠菌中180种潜在的细胞表面蛋白，包括已知的细胞表面粘附素AM和其他细胞表面抗原，如Pra1和Csa1。选择6个蛋白（命名为Csf1-6细胞表面因子）进行进一步的生物学表征。首先，我们验证了选定的CSF基因以酵母和/或菌丝形式表达，然后我们研究了每个CSF基因的缺失对细胞壁完整性、丝化、与哺乳动物细胞的粘附和毒力的影响。因此，我们发现Csf4是一种假定的糖苷酶，在酿酒酵母（Utr2）中具有明显的同源物，是细胞壁完整性和维持的重要因素。有趣的是，在体外黏附实验中，CSF4的缺失也导致丝化缺陷，减少对哺乳动物细胞的粘附，并延长播散性念珠菌病免疫活性小鼠模型的存活时间。还观察到关键器官（如肾脏）的定植延迟，这与esf4缺失菌株的毒力降低一致。这些数据表明细胞外糖苷酶在真菌发病机制中的关键作用，并为治疗和预防真菌疾病的治疗干预提供了新的途径。版权所有：John Wiley Sons， Ltd. 2004
Cell-surface proteins are attractive targets for the development of novel antifungals as they are more accessible to drugs than are intracellular targets. By using a computational biology approach, we identified 180 potential cell-surface proteins in Candida albicans, including the known cell-surface adhesin AM and other cell-surface antigens, such as Pra1 and Csa1. Six proteins (named Csf1-6 for cell-surface factors) were selected for further biological characterization. First, we verified that the selected CSF genes are expressed in the yeast and/or hyphal form and then we investigated the effect of the loss of each CSF gene on cell-wall integrity, filamentation, adhesion to mammalian cells and virulence. As a result, we identified Csf4, a putative glycosidase with an apparent orthologue in Saccharomyces cerevisiae (Utr2), as an important factor for cell-wall integrity and maintenance. Interestingly, deletion of CSF4 also resulted in a defect in filamentation, a reduction in adherence to mammalian cells in an in vitro adhesion assay, and a prolongation of survival in an immunocompetent mouse model of disseminated candidiasis. A delay in colonization of key organs (e.g. kidney) was also observed, which is consistent with a reduction in virulence of the esf4-deletion strain. These data indicate a key role for extracellular glycosidases in fungal pathogenesis and represent a new site for therapeutic intervention to cure and prevent fungal disease. Copyright (C) 2004 John Wiley Sons, Ltd.