The spatial distribution of the exocyst and actin cortical patches is sufficient to organize hyphal tip growth.
The spatial distribution of the exocyst and actin cortical patches is sufficient to organize hyphal tip growth.
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DOI：
10.1128/ec.00085-13
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发表时间：
2013-07
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影响因子：
--
通讯作者：
Craven CJ
中科院分区：
文献类型：
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作者：
Caballero-Lima D;Kaneva IN;Watton SP;Sudbery PE;Craven CJ
在白色念珠菌的菌丝端，我们对(i)胞囊成分，（ii） Rho1, (1,3)-β-葡聚糖合成酶的调节亚基，（iii） Rho1的特化鸟嘌呤核苷酸交换因子（GEF） Rom2，以及（iv）肌动蛋白皮质斑块，内噬作用位点进行了详细的定量测量。基于囊泡与菌丝尖端融合的速率取决于囊泡成分的局部密度这一命题，我们利用所得数据构建并测试了真菌菌丝生长的定量三维模型。像(1,3)-β-葡聚糖合成酶这样嵌入质膜的酶继续合成细胞壁，直到它们被内吞作用除去。该模型成功地预测了菌丝的形状和尺寸，前提是内吞作用可以去除肌动蛋白斑块底部的细胞壁合成酶。此外，该模型的一个关键预测是，合酶的分布比囊泡占据的区域要宽得多。我们的定量测量证实了这一预测。因此，尽管该模型强调了需要进一步研究的细节问题，但总的来说，真菌菌丝尖端生长的模式可以通过一个简单而定量的模型来令人满意地解释，该模型植根于已知的极化生长的分子过程。此外，该方法可以很容易地适应于模拟其他形式的极化生长，例如发生在植物花粉管中的极化生长。
In the hyphal tip of Candida albicans we have made detailed quantitative measurements of (i) exocyst components, (ii) Rho1, the regulatory subunit of (1,3)-β-glucan synthase, (iii) Rom2, the specialized guanine-nucleotide exchange factor (GEF) of Rho1, and (iv) actin cortical patches, the sites of endocytosis. We use the resulting data to construct and test a quantitative 3-dimensional model of fungal hyphal growth based on the proposition that vesicles fuse with the hyphal tip at a rate determined by the local density of exocyst components. Enzymes such as (1,3)-β-glucan synthase thus embedded in the plasma membrane continue to synthesize the cell wall until they are removed by endocytosis. The model successfully predicts the shape and dimensions of the hyphae, provided that endocytosis acts to remove cell wall-synthesizing enzymes at the subapical bands of actin patches. Moreover, a key prediction of the model is that the distribution of the synthase is substantially broader than the area occupied by the exocyst. This prediction is borne out by our quantitative measurements. Thus, although the model highlights detailed issues that require further investigation, in general terms the pattern of tip growth of fungal hyphae can be satisfactorily explained by a simple but quantitative model rooted within the known molecular processes of polarized growth. Moreover, the methodology can be readily adapted to model other forms of polarized growth, such as that which occurs in plant pollen tubes.