The Candida albicans Sur7 Protein Is Needed for Proper Synthesis of the Fibrillar Component of the Cell Wall That Confers Strength
The Candida albicans Sur7 Protein Is Needed for Proper Synthesis of the Fibrillar Component of the Cell Wall That Confers Strength
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DOI：
10.1128/ec.00167-10
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发表时间：
2011-01-01
期刊：
影响因子：
--
通讯作者：
Konopka, James B.
中科院分区：
文献类型：
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作者：
Wang, Hong X.;Douglas, Lois M.;Konopka, James B.
白色念珠菌质膜在与环境的接触、形态发生和细胞壁合成等方面起着重要的作用。我们分析了Sur7蛋白在细胞壁结构和功能中的作用，因为先前的研究表明，这种质膜蛋白是防止细胞壁细胞内异常生长所必需的。Sur7定位于质膜上被称为MCC （Can1占据的膜室）的稳定斑块，这些斑块与酶同体蛋白相关。sur7 Delta突变细胞对加剧细胞壁缺陷的因素表现出更高的敏感性，如洗涤剂（SDS）和几丁质结合剂钙白和刚果红。sur7 δ细胞对阻断细胞壁几丁质（nikkomycin Z）和-1,3-葡聚糖（caspofungin）合成的抑制剂也略敏感。相比之下，与Sur7类似的Fmp45也定位于点状质膜斑块，在细胞壁合成中没有可检测到的作用。细胞壁成分的化学分析表明，sur7 δ细胞含有较低水平的β -葡聚糖，这是一种赋予细胞壁刚性的葡萄糖聚合物。与此一致的是，Sur7 Delta细胞对裂解更敏感，可以通过增加培养基的渗透压来部分挽救裂解。有趣的是，Sur7存在于静态斑块中，而-1,3-葡聚糖合成酶在质膜中是移动的，通常与肌动蛋白斑块有关。因此，Sur7可能间接影响β -葡聚糖合成，可能是通过改变定位于MCC和酶同体结构域的细胞信号组件的功能。
The Candida albicans plasma membrane plays important roles in interfacing with the environment, morphogenesis, and cell wall synthesis. The role of the Sur7 protein in cell wall structure and function was analyzed, since previous studies showed that this plasma membrane protein is needed to prevent abnormal intracellular growth of the cell wall. Sur7 localizes to stable patches in the plasma membrane, known as MCC (membrane compartment occupied by Can1), that are associated with eisosome proteins. The sur7 Delta mutant cells displayed increased sensitivity to factors that exacerbate cell wall defects, such as detergent (SDS) and the chitin-binding agents calcofluor white and Congo red. The sur7 Delta cells were also slightly more sensitive to inhibitors that block the synthesis of cell wall chitin (nikkomycin Z) and beta-1,3-glucan (caspofungin). In contrast, Fmp45, a paralog of Sur7 that also localizes to punctate plasma membrane patches, did not have a detectable role in cell wall synthesis. Chemical analysis of cell wall composition demonstrated that sur7 Delta cells contain decreased levels of beta-glucan, a glucose polymer that confers rigidity on the cell wall. Consistent with this, Sur7 Delta cells were more sensitive to lysis, which could be partially rescued by increasing the osmolarity of the medium. Interestingly, Sur7 is present in static patches, whereas beta-1,3-glucan synthase is mobile in the plasma membrane and is often associated with actin patches. Thus, Sur7 may influence beta-glucan synthesis indirectly, perhaps by altering the functions of the cell signaling components that localize to the MCC and eisosome domains.