Myosin X transports Mena/VASP to the tip of filopodia
Myosin X transports Mena/VASP to the tip of filopodia
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DOI：
10.1016/j.bbrc.2004.04.167
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发表时间：
2004-06-18
影响因子：
3.1
通讯作者：
Ikebe, M
中科院分区：
文献类型：
--
作者：
Tokuo, H;Ikebe, M
肌球蛋白 X (M10) 是一种基于双头肌动蛋白的马达，在多种细胞类型中表达，被认为在哺乳动物细胞中的货物运动中发挥作用，但其细胞功能尚不清楚。在这里，我们发现 M10 与 Mena/VASP 结合，Mena/VASP 通过与肌动蛋白加帽蛋白竞争来促进肌动蛋白聚合。免疫细胞化学显示内源性 M10 与 Mena/VASP 共定位于丝状伪足的尖端。一致地，EGFP-M10 和 RFP-VASP 均在丝状伪足的尖端发现。结果提出了一个假设：NI 10 将 Mena/VASP 转运至丝状伪足的尖端。支持这一观点的是，丝状伪足尖端的 VASP 数量与 M10 的数量成正比。此外，我们在荧光显微镜下直接观察到活 HeLa 细胞中 M10 和 VASP 的运动。 EGFP-M10 和 RFP-VASP 一起从丝状伪足的根部移动到尖端。有趣的是，丝状伪足尖端的M10含量与丝状伪足的长度呈线性相关，这与VASP的肌动蛋白丝延伸功能一致。这些结果表明，M10 是一种特殊的马达，将 Mena/VASP 从丝状伪足的根部运送到发生肌动蛋白丝延伸的尖端。 (C) 2004 Elsevier Inc. 保留所有权利。
Myosin X (M10) is a two-headed actin based motor expressed in a variety of cell types, that is thought to play a role in cargo movement in mammalian cells, but its cellular function is unknown. Here we found that M10 binds to Mena/VASP, which facilitates actin polymerization by competing with actin capping proteins. Immunocytochemistry revealed that endogenous M10 co-localized with Mena/VASP at the tip of filopodia. Consistently, both EGFP-M10 and RFP-VASP were found at the tip of filopodia. The result raises a hypothesis that NI 10 transports Mena/VASP towards the tip of filopodia. Supporting this idea, the amount of VASP at the tip of filopodia was proportional to that of M10. Furthermore, we directly visualized the movement of M10 and VASP in living HeLa cells under fluorescence microscope. EGFP-M10 and RFP-VASP move together from the root to the tip of the filopodia. Interestingly, the amount of M10 at the tip of filopodia was linearly related to the length of filopodia, consistent with the actin filament extending function of VASP. These results show that M10 is a specific motor carrying Mena/VASP from the root to the tip of the filopodia where extension of actin filament takes place. (C) 2004 Elsevier Inc. All rights reserved.