ADP-ribosylation factor machinery mediates endocytosis in plant cells
ADP-ribosylation factor machinery mediates endocytosis in plant cells
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DOI：
10.1073/pnas.1016260107
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发表时间：
2010-12-14
影响因子：
11.1
通讯作者：
Friml, Jiri
中科院分区：
文献类型：
--
作者：
Naramoto, Satoshi;Kleine-Vehn, Jurgen;Friml, Jiri
胞吞作用对多细胞生物的各种细胞功能和发育至关重要。在哺乳动物和酵母中，adp -核糖基化因子（ARF） gtpase是囊泡形成的关键组分，其调控因子ARF-鸟嘌呤核苷酸交换因子（GEFs）和ARF- gtpase激活蛋白（GAPs）介导胞吞作用。类似的作用尚未在植物中确定，主要是因为缺乏其他真核生物中参与内吞作用的典型ARF和ARF- gef成分。在这项研究中，我们揭示了一种基于ARF GTPase活性的植物内吞调节机制。我们发现，ARF-GEF GNOM和ARF-GAP血管网络缺陷3 （VAN3）都参与极性生长素转运依赖的形态发生，它们定位于质膜和细胞内结构。变角度荧光显微镜显示，GNOM和VAN3定位于与内噬囊泡外壳网格蛋白相关的质膜上部分重叠的离散灶。遗传学研究表明，GNOM和VAN3活性是质膜蛋白（包括pin形成的生长素转运蛋白）内吞和内化所必需的。这些发现确定了植物中基于ARF gtpase的内吞作用调控机制。GNOM和VAN3先前被认为分别仅在循环核内体和反式高尔基网络中起作用。因此，我们的发现揭示了这些突出的发育调节因子的额外细胞功能。
Endocytosis is crucial for various cellular functions and development of multicellular organisms. In mammals and yeast, ADP-ribosylation factor (ARF) GTPases, key components of vesicle formation, and their regulators ARF-guanine nucleotide exchange factors (GEFs) and ARF-GTPase-activating protein (GAPs) mediate endocytosis. A similar role has not been established in plants, mainly because of the lack of the canonical ARF and ARF-GEF components that are involved in endocytosis in other eukaryotes. In this study, we revealed a regulatory mechanism of endocytosis in plants based on ARF GTPase activity. We identified that ARF-GEF GNOM and ARF-GAP VASCULAR NETWORK DEFECTIVE 3 (VAN3), both of which are involved in polar auxin transport-dependent morphogenesis, localize at the plasma membranes as well as in intracellular structures. Variable angle epifluorescence microscopy revealed that GNOM and VAN3 localize to partially overlapping discrete foci at the plasma membranes that are regularly associated with the endocytic vesicle coat clathrin. Genetic studies revealed that GNOM and VAN3 activities are required for endocytosis and internalization of plasma membrane proteins, including PIN-FORMED auxin transporters. These findings identified ARF GTPase-based regulatory mechanisms for endocytosis in plants. GNOM and VAN3 previously were proposed to function solely at the recycling endosomes and trans-Golgi networks, respectively. Therefore our findings uncovered an additional cellular function of these prominent developmental regulators.