The kinesin-related protein MCAK is a microtubule depolymerase that forms an ATP-hydrolyzing complex at microtubule ends
The kinesin-related protein MCAK is a microtubule depolymerase that forms an ATP-hydrolyzing complex at microtubule ends
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DOI：
10.1016/s1097-2765(03)00049-2
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发表时间：
2003-02-01
期刊：
影响因子：
16
通讯作者：
Howard, J
中科院分区：
文献类型：
--
作者：
Hunter, AW;Caplow, M;Howard, J
MCAK属于运动蛋白相关蛋白的Kin I亚家族，这是一组独特的运动蛋白，它们不运动，而是破坏微管的稳定。我们发现MCAK是一种atp酶，通过加速微管末端微管蛋白解离速率100倍来催化微管解聚。MCAK在每个原丝末端有一个高亲和力的结合位点，当被占用时，它同时具有解聚合酶和atp酶的活性。MCAK非常迅速地靶向原丝末端（导通率为54 muM(-1)）。S(-1))，可能是通过沿着微管晶格扩散，一旦在那里，以1s（-1）的速率去除大约20个微管蛋白二聚体。我们提出，多达14个MCAK二聚体聚集在微管末端，形成atp水解复合物，使微管逐渐解聚。
MCAK belongs to the Kin I subfamily of kinesin-related proteins, a unique group of motor proteins that are not motile but instead destabilize microtubules. We show that MCAK is an ATPase that catalytically depolymerizes microtubules by accelerating, 100-fold, the rate of dissociation of tubulin from microtubule ends. MCAK has one high-affinity binding site per protofilament end, which, when occupied, has both the depolymerase and ATPase activities. MCAK targets protofilament ends very rapidly (on-rate 54 muM(-1).s(-1)), perhaps by diffusion along the microtubule lattice and, once there, removes similar to20 tubulin dimers at a rate of 1 s(-1). We propose that up to 14 MCAK dimers assemble at the end of a microtubule to form an ATP-hydrolyzing complex that processively depolymerizes the microtubule.