Hyphal tip-associated localization of Cdc42 is F-actin dependent in Candida albicans
Hyphal tip-associated localization of Cdc42 is F-actin dependent in Candida albicans
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DOI：
10.1128/ec.1.6.856-864.2002
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发表时间：
2002-12-01
期刊：
影响因子：
--
通讯作者：
Liu, HP
中科院分区：
文献类型：
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作者：
Hazan, I;Liu, HP
Rho型GTP酶CDc42对于真核细胞极性的建立和维持是重要的。为了研究CDC42在白念珠菌从酵母到菌丝的转化过程中是否受到调控，我们构建了ACT1启动子下的绿色荧光蛋白(GFP)-CDC42融合蛋白，并观察了其在白念珠菌活细胞中的定位。与酿酒酵母一样，GFP-CDC42存在于细胞的整个周缘。在白色念珠菌的酵母状细胞中，它聚集在小芽的顶端和侧面，以及大芽细胞的母子颈部。在菌丝诱导过程中，GFP-CDC42聚集在菌丝外翻部位，并停留在菌丝顶端。CDC42的这种时间和空间定位表明，它的活性在酵母到菌丝的转变过程中受到调节。在经过核分离的细胞中，除了菌丝顶端的聚集外，GFP-CDC42也被认为是菌丝管内的一条带。利用F-肌动蛋白组装抑制剂Latrunculin A，我们发现在酵母细胞中，GFP-CDC42在芽位的积累不依赖于F-肌动蛋白，而GFP-CDC42在菌丝顶端的积累需要F-肌动蛋白。此外，F-肌动蛋白细胞骨架的破坏削弱了菌丝特异基因的转录诱导。因此，菌丝的形成类似于酿酒酵母的交配，都需要F-肌动蛋白来定位GFP-CDC42和有效的信号转导。
The rho-type GTPase Cdc42 is important for the establishment and maintenance of eukaryotic cell polarity. To examine whether Cdc42 is regulated during the yeast-to-hypha transition in Candida albicans, we constructed a green fluorescence protein (GFP)-Cdc42 fusion under the ACT1 promoter and observed its localization in live C. albicans cells. As in Saccharomyces cerevisiae, GFP-Cdc42 was observed around the entire periphery of the cell. In yeast-form cells of C. albicans, it clustered to the tips and sides of small buds as well as to the mother-daughter neck region of large-budded cells. Upon hyphal induction, GFP-Cdc42 clustered to the site of hyphal evagination and remained at the tips of the hyphae. This temporal and spatial localization of Cdc42 suggests that its activity is regulated during the yeast-to-hypha transition. In addition to the accumulation at the hyphal tip, GFP-Cdc42 was also seen as a band within the hyphal tube in cells that had undergone nuclear separation. With the F-actin-assembly inhibitor latrunculin A, we found that GFP-Cdc42 accumulation at the bud site in yeast-form cells is F-actin independent, whereas GFP-Cdc42 accumulation at the hyphal tip requires F-actin. Furthermore, disruption of the F-actin cytoskeleton impaired the transcriptional induction of hypha-specific genes. Therefore, hypha formation resembles mating in Saccharomyces cerevisiae in that both require F-actin for GFP-Cdc42 localization and efficient signaling.