Clathrin Mediates Endocytosis and Polar Distribution of PIN Auxin Transporters in Arabidopsis
Clathrin Mediates Endocytosis and Polar Distribution of PIN Auxin Transporters in Arabidopsis
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DOI：
10.1105/tpc.111.083030
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发表时间：
2011-05-01
期刊：
影响因子：
11.6
通讯作者：
Friml, Jiri
中科院分区：
文献类型：
--
作者：
Kitakura, Saeko;Vanneste, Steffen;Friml, Jiri
内吞作用是真核细胞内化细胞外和质膜物质的重要机制，在单细胞和多细胞生物体的许多细胞和发育过程中都需要内吞作用。在动物和酵母中，最具特征性的内吞途径取决于囊泡外壳蛋白cathrin的功能。最近在植物细胞中也证实了笼蛋白介导的内吞作用，但其生理和发育作用尚不清楚。在这里，我们通过遗传手段评估了笼状蛋白介导的内吞作用机制在植物中的作用。我们在拟南芥中通过突变体和显性-负性方法干扰了cathrin Heavy Chain(CHC)的功能，并建立了以细胞类型特异性的方式操纵cathrin功能的工具。Chc2单一突变体和显性负性CHC1(HUB)转基因系在大量内吞和显著的质膜蛋白内化方面存在缺陷。干扰网状蛋白介导的内吞作用导致PIN生长素转运蛋白的结构性内吞循环及其在胚胎和根中的极地分布的缺陷。与此一致的是，这些品系改变了生长素的分布模式和相关的生长素运输相关的表型，如异常的胚胎模式，不完善的子叶规格，向外生长，以及侧根器官发生受损。综上所述，这些数据表明，笼蛋白功能在植物的细胞极性、生长、构型和器官发生中起着重要作用。
Endocytosis is a crucial mechanism by which eukaryotic cells internalize extracellular and plasma membrane material, and it is required for a multitude of cellular and developmental processes in unicellular and multicellular organisms. In animals and yeast, the best characterized pathway for endocytosis depends on the function of the vesicle coat protein clathrin. Clathrin-mediated endocytosis has recently been demonstrated also in plant cells, but its physiological and developmental roles remain unclear. Here, we assessed the roles of the clathrin-mediated mechanism of endocytosis in plants by genetic means. We interfered with clathrin heavy chain (CHC) function through mutants and dominant-negative approaches in Arabidopsis thaliana and established tools to manipulate clathrin function in a cell type-specific manner. The chc2 single mutants and dominant-negative CHC1 (HUB) transgenic lines were defective in bulk endocytosis as well as in internalization of prominent plasma membrane proteins. Interference with clathrin-mediated endocytosis led to defects in constitutive endocytic recycling of PIN auxin transporters and their polar distribution in embryos and roots. Consistent with this, these lines had altered auxin distribution patterns and associated auxin transport-related phenotypes, such as aberrant embryo patterning, imperfect cotyledon specification, agravitropic growth, and impaired lateral root organogenesis. Together, these data demonstrate a fundamental role for clathrin function in cell polarity, growth, patterning, and organogenesis in plants.