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首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >The Kinesin-1 Motor Protein Is Regulated By A Direct Interaction Of Its Head And Tail
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The Kinesin-1 Motor Protein Is Regulated By A Direct Interaction Of Its Head And Tail

机译：Kinesin-1运动蛋白受其头尾直接相互作用的调节。

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Kinesin-1 is a molecular motor protein that transports cargo along microtubules. Inside cells, the vast majority of kinesin-1 is regulated to conserve ATP and to ensure its proper intracellular distribution and coordination with other molecular motors. Regulated kinesin-1 folds in half at a hinge in its coiled-coil stalk. Interactions between coiled-coil regions near the enzymatically active heads at the N terminus and the regulatory tails at the C terminus bring these globular elements in proximity and stabilize the folded conformation. However, it has remained a mystery how kinesin-1's microtubule-stimulated ATPase activity is regulated in this folded conformation. Here, we present evidence for a direct interaction between the kinesin-1 head and tail. We photochemically cross-linked heads and tails and produced an 8-A cryoEM reconstruction of the cross-linked head-tail complex on microtubules. These data demonstrate that a conserved essential regulatory element in the kinesin-1 tail interacts directly and specifically with the enzymatically critical Switch I region of the head. This interaction suggests a mechanism for tail-mediated regulation of the ATPase activity of kinesin-1. In our structure, the tail makes simultaneous contacts with the kinesin-1 head and the microtubule, suggesting the tail may both regulate kinesin-1 in solution and hold it in a paused state with high ADP affinity on microtubules. The interaction of the Switch I region of the kinesin-1 head with the tail is strikingly similar to the interactions of small GTPases with their regulators, indicating that other kinesin motors may share similar regulatory mechanisms.
机译：Kinesin-1是一种分子运动蛋白，可沿着微管运输货物。在细胞内部，绝大多数的kinesin-1被调节以保存ATP并确保其在细胞内的适当分布并与其他分子马达协调。调节的驱动蛋白1在其卷曲螺旋茎中的铰链处折叠成一半。 N末端酶促活性头附近的卷曲螺旋区域与C末端调节尾部之间的相互作用使这些球形元素接近并稳定了折叠构象。然而，如何在这种折叠构象中调节驱动蛋白-1的微管刺激的ATPase活性仍是一个谜。在这里，我们为驱动蛋白1头和尾之间的直接相互作用提供了证据。我们光化学交联的头​​和尾，并在微管上产生了交联的头尾复合体的8-A cryoEM重建。这些数据表明，在驱动蛋白1尾部中保守的必需调节元件直接且特异性地与头部的酶促关键的Switch I区相互作用。这种相互作用表明尾巴介导的驱动蛋白1 ATPase活性的调节机制。在我们的结构中，尾巴与kinesin-1头部和微管同时接触，这表明尾巴既可以调节溶液中的kinesin-1，又可以将其保持在暂停状态，并且对微管具有很高的ADP亲和力。 kinesin-1头部的Switch I区与尾部的相互作用极其类似于小型GTPases及其调节剂的相互作用，这表明其他驱动蛋白的马达可能共享相似的调控机制。

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