Coronin 1C harbours a second actin-binding site that confers co-operative binding to F-actin.
Coronin 1C harbours a second actin-binding site that confers co-operative binding to F-actin.
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DOI：
10.1042/bj20120209
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发表时间：
2012-05-15
期刊：
影响因子：
--
通讯作者：
Bear JE
中科院分区：
文献类型：
--
作者：
Chan KT;Roadcap DW;Holoweckyj N;Bear JE
肌动蛋白细丝网络的动态重排对细胞的运动、吞噬和内吞作用至关重要。冠状体能与F-肌动蛋白(丝状肌动蛋白)结合，从而促进了这些过程。我们以前在体外和体内都发现了一个保守的表面暴露的精氨酸(Arg30)，它位于柯拉宁1B的β推进器中，是F-肌动蛋白结合所必需的。然而，这一发现是否适用于其他冠脉还没有很好的定义。通过肌动蛋白结合的定量分析，我们发现，突变等量残基会取消柯拉宁1A中的F-肌动蛋白结合，但不会取消柯拉宁1C中的F-肌动蛋白结合。通过诱变和生物化学竞争，我们在柯拉宁1C的独特区域确定了第二个肌动蛋白结合位点。有趣的是，科罗宁1C在成纤维细胞中的前沿定位需要β推进器中的保守位置，而不是独特区域中的位置。此外，与柯罗宁1A和柯罗宁1B相比，柯罗宁1C显示出与肌动蛋白细丝高度协同的结合。在目前的研究中，我们强调了一种新的冠状体素调节模式，它对冠状体素如何协调细胞骨架动力学有一定的影响。
Dynamic rearrangement of actin filament networks is critical for cell motility, phagocytosis and endocytosis. Coronins facilitate these processes, in part, by their ability to bind F-actin (filamentous actin). We previously identified a conserved surface-exposed arginine (Arg30) in the β-propeller of Coronin 1B required for F-actin binding in vitro and in vivo. However, whether this finding translates to other coronins has not been well defined. Using quantitative actin-binding assays, we show that mutating the equivalent residue abolishes F-actin binding in Coronin 1A, but not Coronin 1C. By mutagenesis and biochemical competition, we have identified a second actin-binding site in the unique region of Coronin 1C. Interestingly, leading-edge localization of Coronin 1C in fibroblasts requires the conserved site in the β-propeller, but not the site in the unique region. Furthermore, in contrast with Coronin 1A and Coronin 1B, Coronin 1C displays highly co-operative binding to actin filaments. In the present study, we highlight a novel mode of coronin regulation, which has implications for how coronins orchestrate cytoskeletal dynamics.