Twinfilin is an actin-filament-severing protein and promotes rapid turnover of actin structures in vivo
Twinfilin is an actin-filament-severing protein and promotes rapid turnover of actin structures in vivo
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DOI：
10.1242/jcs.02860
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发表时间：
2006-04-15
影响因子：
4
通讯作者：
Goode, BL
中科院分区：
文献类型：
--
作者：
Moseley, JB;Okada, K;Goode, BL
协同工作，多个肌动蛋白结合蛋白调节肌动蛋白网络的动态营业额。在这里，我们定义了一个新的功能，保守的肌动蛋白结合蛋白twinfilin，直到现在被认为主要作为一个单体螯合蛋白的功能。我们表明，纯化的芽殖酵母twinfilin（Twf 1）结合，并切断肌动蛋白丝在体外pH值低于6.0散装动力学和荧光显微镜检测。此外，我们使用全内反射荧光（TIRF）显微镜来证明Twf 1可以真实的实时切断单个肌动蛋白丝。它已被证明，加帽蛋白直接结合到Twf 1和所需的Twf 1本地化皮层肌动蛋白补丁在体内。我们证明，加帽蛋白直接抑制切断活动的Twf 1，第一生化功能归因于这种相互作用。此外，磷脂酰肌醇（4，5）-二磷酸[PtdIns（4，5）P-2]抑制Twf 1的切割活性。与这些生物化学活动相一致的是，twf 1 Delta突变导致活细胞中皮质肌动蛋白斑块周转率降低。总之，我们的数据表明，twinfilin协调丝切断和单体螯合在网站的快速肌动蛋白营业额，并控制多个监管输入。
Working in concert, multiple actin-binding proteins regulate the dynamic turnover of actin networks. Here, we define a novel function for the conserved actin-binding protein twinfilin, which until now was thought to function primarily as a monomer-sequestering protein. We show that purified budding yeast twinfilin (Twf1) binds to and severs actin filaments in vitro at pH below 6.0 in bulk kinetic and fluorescence microscopy assays. Further, we use total internal reflection fluorescence (TIRF) microscopy to demonstrate that Twf1 severs individual actin filaments in real time. It has been shown that capping protein directly binds to Twf1 and is required for Twf1 localization to cortical actin patches in vivo. We demonstrate that capping protein directly inhibits the severing activity of Twf1, the first biochemical function ascribed to this interaction. In addition, phosphatidylinositol (4,5)-bisphosphate [PtdIns(4,5) P-2] inhibits Twf1 filament-severing activity. Consistent with these biochemical activities, a twf1 Delta mutation causes reduced rates of cortical actin patch turnover in living cells. Together, our data suggest that twinfilin coordinates filament severing and monomer sequestering at sites of rapid actin turnover and is controlled by multiple regulatory inputs.