The Sur7 Protein Regulates Plasma Membrane Organization and Prevents Intracellular Cell Wall Growth in Candida albicans
The Sur7 Protein Regulates Plasma Membrane Organization and Prevents Intracellular Cell Wall Growth in Candida albicans
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DOI：
10.1091/mbc.e08-05-0479
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发表时间：
2008-12-01
影响因子：
3.3
通讯作者：
Konopka, James B.
中科院分区：
文献类型：
--
作者：
Alvarez, Francisco J.;Douglas, Lois M.;Konopka, James B.
白色念珠菌质膜在细胞生长中起着重要作用，并作为抗真菌药物的靶点。对Ca-Sur 7的分析表明，这种四个跨膜结构域的蛋白定位于稳定的点状斑块，类似于在S.啤酒。Ca-Sur 7的定位依赖于鞘脂的合成。与S. cerevisiae，a C.白念珠菌sur 7 Delta突变体在胞吞和形态发生方面表现出缺陷。细胞膜蛋白和肌动蛋白定位错误，细胞壁合成非常异常，包括细胞壁向细胞质中的长突起。sur 7 Delta突变体的几种表型与抑制β-葡聚糖合酶的效果相似，表明异常细胞壁合成与胁迫条件下观察到的几丁质合酶活性的激活有关。这些结果通过证明Sur 7是适当的质膜组织和细胞壁合成所需的，扩展了eisosomes的作用。真菌Sur 7蛋白的第一胞外环中的保守Cys基序类似于在动物细胞中形成紧密连接的claudin蛋白的特征基序，这表明这些四跨膜蛋白在形成专门的质膜结构域中的共同作用。
The Candida albicans plasma membrane plays important roles in cell growth and as a target for antifungal drugs. Analysis of Ca-Sur7 showed that this four transmembrane domain protein localized to stable punctate patches, similar to the plasma membrane subdomains known as eisosomes or MCC that were discovered in S. cerevisiae. The localization of Ca-Sur7 depended on sphingolipid synthesis. In contrast to S. cerevisiae, a C. albicans sur7 Delta mutant displayed defects in endocytosis and morphogenesis. Septins and actin were mislocalized, and cell wall synthesis was very abnormal, including long projections of cell wall into the cytoplasm. Several phenotypes of the sur7 Delta mutant are similar to the effects of inhibiting beta-glucan synthase, suggesting that the abnormal cell wall synthesis is related to activation of chitin synthase activity seen under stress conditions. These results expand the roles of eisosomes by demonstrating that Sur7 is needed for proper plasma membrane organization and cell wall synthesis. A conserved Cys motif in the first extracellular loop of fungal Sur7 proteins is similar to a characteristic motif of the claudin proteins that form tight junctions in animal cells, suggesting a common role for these tetraspanning membrane proteins in forming specialized plasma membrane domains.