A RhoGDP dissociation inhibitor spatially regulates growth in root hair cells
A RhoGDP dissociation inhibitor spatially regulates growth in root hair cells
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DOI：
10.1038/nature04198
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发表时间：
2005-12-15
期刊：
影响因子：
64.8
通讯作者：
Dolan, L
中科院分区：
文献类型：
--
作者：
Carol, RJ;Takeda, S;Dolan, L
根毛是从根表面延伸到土壤中的细胞突起；在那里，它们提供了接触固定无机离子的途径，如磷酸盐，这是生长所必需的。它们的圆柱形是由称为尖端生长的细胞扩张的极化机制造成的，在这种机制中，伸长被限制在毛发形成细胞(毛母细胞)顶端(2-4)表面的一小块区域。在这里，我们通过分离在毛发母细胞上形成异位生长位点的拟南芥突变体(Scn1)来识别在空间上控制细胞生长的蛋白质。我们克隆了SCN1，并证明SCN1是一种RhoGTPase GDP解离抑制物(RhoGDI)，它在空间上将生长部位限制在毛母细胞上的一个点上。我们以前证明了RHD2/AtrbohC NADPH氧化酶局部产生活性氧是毛发生长所必需的(5)；在这里，我们证明SCN1/AtrhoGDI1是在野生型发育过程中将RHD2/AtrbohC催化的活性氧产生集中到毛发尖端的机制的一个组成部分。我们认为，植物细胞生长的空间组织需要RhoGDI调节的局部RHD2/AtrbohC NADPH氧化酶的激活。
Root hairs are cellular protuberances extending from the root surface into the soil; there they provide access to immobile inorganic ions such as phosphate, which are essential for growth(1). Their cylindrical shape results from a polarized mechanism of cell expansion called tip growth in which elongation is restricted to a small area at the surface of the hair-forming cell (trichoblast) tip(2-4). Here we identify proteins that spatially control the sites at which cell growth occurs by isolating Arabidopsis mutants (scn1) that develop ectopic sites of growth on trichoblasts. We cloned SCN1 and showed that SCN1 is a RhoGTPase GDP dissociation inhibitor ( RhoGDI) that spatially restricts the sites of growth to a single point on the trichoblast. We showed previously that localized production of reactive oxygen species by RHD2/AtrbohC NADPH oxidase is required for hair growth(5); here we show that SCN1/AtrhoGDI1 is a component of the mechanism that focuses RHD2/AtrbohC-catalysed production of reactive oxygen species to hair tips during wild-type development. We propose that the spatial organization of growth in plant cells requires the local RhoGDI-regulated activation of the RHD2/AtrbohC NADPH oxidase.