In Candida albicans, phosphorylation of Exo84 by Cdk1-Hgc1 is necessary for efficient hyphal extension.
In Candida albicans, phosphorylation of Exo84 by Cdk1-Hgc1 is necessary for efficient hyphal extension.
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DOI：
10.1091/mbc.e13-11-0688
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发表时间：
2014-04
影响因子：
3.3
通讯作者：
Sudbery PE
中科院分区：
文献类型：
--
作者：
Caballero-Lima D;Sudbery PE
白色念珠菌菌丝在整个有丝分裂过程中持续生长，并且Cdk对Exo 84的磷酸化是有效菌丝生长所必需的。相比之下，Cdk对Exo 84的磷酸化会阻止酿酒酵母中的细胞生长。Cdk 1靶位点在Exo 84中的位置解释了磷酸调节如何介导这些不同的生长模式。外囊是一种保守的多蛋白复合物，在与质膜融合之前束缚分泌囊泡，因此它对细胞表面扩张至关重要。在酿酒酵母和哺乳动物细胞中，细胞表面扩张在有丝分裂期间停止。In S.在酿酒酵母中，有丝分裂期间Cdk 1-Clb 2对外囊组分Exo 84的磷酸化导致外囊解体。在这里，我们表明，人类真菌病原体白色念珠菌的菌丝继续延伸到整个有丝分裂。我们表明，CaExo 84是磷酸化的Cdk 1，这是必要的有效的菌丝延伸。Cdk 1的这种作用依赖于菌丝特异性细胞周期蛋白Hgc 1，即芽殖酵母中G1细胞周期蛋白的同源物。CaExo 84的磷酸化不会改变其定位，但会改变其对磷脂酰丝氨酸的亲和力，使其在质膜上再循环。Cdk 1对CaExo 84和ScExo 84的不同作用与Cdk 1在两种蛋白中的靶位点的不同位置一致。因此，这种保守的极化生长的组成部分已经进化，使其磷酸化调节介导的显着不同的模式，这两种生物体的增长。
Candida albicans hyphae continue to grow throughout mitosis, and phosphorylation of Exo84 by Cdk is necessary for efficient hyphal growth. In contrast, phosphorylation of Exo84 by Cdk halts cell growth in Saccharomyces cerevisiae. The location of Cdk1 target sites in Exo84 explains how phosphoregulation mediates these different patterns of growth. The exocyst, a conserved multiprotein complex, tethers secretory vesicles before fusion with the plasma membrane; thus it is essential for cell surface expansion. In both Saccharomyces cerevisiae and mammalian cells, cell surface expansion is halted during mitosis. In S. cerevisiae, phosphorylation of the exocyst component Exo84 by Cdk1-Clb2 during mitosis causes the exocyst to disassemble. Here we show that the hyphae of the human fungal pathogen Candida albicans continue to extend throughout the whole of mitosis. We show that CaExo84 is phosphorylated by Cdk1, which is necessary for efficient hyphal extension. This action of Cdk1 depends on the hyphal-specific cyclin Hgc1, the homologue of G1 cyclins in budding yeast. Phosphorylation of CaExo84 does not alter its localization but does alter its affinity for phosphatidylserine, allowing it to recycle at the plasma membrane. The different action of Cdk1 on CaExo84 and ScExo84 is consistent with the different locations of the Cdk1 target sites in the two proteins. Thus this conserved component of polarized growth has evolved so that its phosphoregulation mediates the dramatically different patterns of growth shown by these two organisms.