Clustering of VASP actively drives processive, WH2 domain-mediated actin filament elongation
Clustering of VASP actively drives processive, WH2 domain-mediated actin filament elongation
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DOI：
10.1038/emboj.2008.211
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发表时间：
2008-11-19
期刊：
影响因子：
11.4
通讯作者：
Faix, Jan
中科院分区：
文献类型：
--
作者：
Breitsprecher, Dennis;Kiesewetter, Antje K.;Faix, Jan
血管舒张刺激磷蛋白（VASP）是动态肌动蛋白结构（如丝状伪足和片状伪足）的关键调节因子，但其在其形成中的确切功能存在争议。使用在体外TIRF显微镜，我们首次表明，人类和网骨藻VASP直接参与加速丝伸长提供单体肌动蛋白不断增长的倒钩结束。在溶液中，DdVASP以浓度依赖性方式显着加速肌动蛋白丝的伸长，但被低浓度的加帽蛋白（CP）抑制。与此形成鲜明对比的是，聚集在功能化珠上的VASP切换到进行性长丝伸长，即使对非常高浓度的CP也变得不敏感。补充与VASP突变体和EM结构的蛋白质的体内分析，我们提出了一种机制，膜相关的VASP寡聚体使用其WH2域的影响，既束缚肌动蛋白丝和他们的进程中的活性肌动蛋白组装的网站伸长。
Vasodilator-stimulated phosphoprotein (VASP) is a key regulator of dynamic actin structures like filopodia and lamellipodia, but its precise function in their formation is controversial. Using in vitro TIRF microscopy, we show for the first time that both human and Dictyostelium VASP are directly involved in accelerating filament elongation by delivering monomeric actin to the growing barbed end. In solution, DdVASP markedly accelerated actin filament elongation in a concentration-dependent manner but was inhibited by low concentrations of capping protein (CP). In striking contrast, VASP clustered on functionalized beads switched to processive filament elongation that became insensitive even to very high concentrations of CP. Supplemented with the in vivo analysis of VASP mutants and an EM structure of the protein, we propose a mechanism by which membrane-associated VASP oligomers use their WH2 domains to effect both the tethering of actin filaments and their processive elongation in sites of active actin assembly.