Actin depolymerizing factor (ADF/cofilin) enhances the rate of filament turnover: implication in actin-based motility.
Actin depolymerizing factor (ADF/cofilin) enhances the rate of filament turnover: implication in actin-based motility.
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肌动蛋白去聚合因子（ADF/Cofilin）提高了细丝流动率：基于肌动蛋白的运动的影响。
DOI：
10.1083/jcb.136.6.1307
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发表时间：
1997-03-24
期刊：
影响因子：
--
通讯作者：
Pantaloni D
中科院分区：
文献类型：
--
作者：
Carlier MF;Laurent V;Santolini J;Melki R;Didry D;Xia GX;Hong Y;Chua NH;Pantaloni D
肌动蛋白解聚因子（ADF）/cofilin家族的肌动蛋白结合蛋白被认为控制肌动蛋白为基础的运动过程。来自拟南芥的ADF 1似乎是一个很好的模型，其功能与该家族的其他成员相似。ADF在肌动蛋白动力学中的功能已经使用物理化学方法和基于肌动蛋白的运动测定的组合进行了研究，在生理离子条件下，在pH 7.8。ADF结合ADP结合形式的G-或F-肌动蛋白的亲和力比ATP-或ADP-Pi结合形式高两个数量级。ADF的一个主要特性是其能够将肌动蛋白丝的体外周转率（旋转研磨）提高到与在活动板状伪足中观察到的体内周转率相当的值。ADF增加单核细胞增生李斯特菌在高度稀释的ADF限制性血小板提取物中的推进速率，并缩短肌动蛋白尾部。这些作用是由ADF参与肌动蛋白丝组装介导的，这导致肌动蛋白丝两端动力学参数的变化。ADF的动力学效应是末端特异性的，并且不能通过长丝切断来解释。主要的功能相关效应是肌动蛋白从尖端解离的速率增加25倍，而从倒刺末端解离的速率不变。在稳态下，单体-聚合物循环的限速步骤的大幅增加是肌动蛋白基能动过程速率增加的原因。总之，ADF的功能不是螯合G-肌动蛋白。ADF在肌动蛋白组装中使用ATP水解来增强细丝动力学。
Actin-binding proteins of the actin depolymerizing factor (ADF)/cofilin family are thought to control actin-based motile processes. ADF1 from Arabidopsis thaliana appears to be a good model that is functionally similar to other members of the family. The function of ADF in actin dynamics has been examined using a combination of physical–chemical methods and actin-based motility assays, under physiological ionic conditions and at pH 7.8. ADF binds the ADPbound forms of G- or F-actin with an affinity two orders of magnitude higher than the ATP- or ADP-Pi– bound forms. A major property of ADF is its ability to enhance the in vitro turnover rate (treadmilling) of actin filaments to a value comparable to that observed in vivo in motile lamellipodia. ADF increases the rate of propulsion of Listeria monocytogenes in highly diluted, ADF-limited platelet extracts and shortens the actin tails. These effects are mediated by the participation of ADF in actin filament assembly, which results in a change in the kinetic parameters at the two ends of the actin filament. The kinetic effects of ADF are end specific and cannot be accounted for by filament severing. The main functionally relevant effect is a 25-fold increase in the rate of actin dissociation from the pointed ends, while the rate of dissociation from the barbed ends is unchanged. This large increase in the rate-limiting step of the monomer-polymer cycle at steady state is responsible for the increase in the rate of actin-based motile processes. In conclusion, the function of ADF is not to sequester G-actin. ADF uses ATP hydrolysis in actin assembly to enhance filament dynamics.