Head-head coordination is required for the processive motion of cytoplasmic dynein, an AAA+ molecular motor
Head-head coordination is required for the processive motion of cytoplasmic dynein, an AAA+ molecular motor
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DOI：
10.1016/j.jsb.2006.03.014
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发表时间：
2006-10-01
影响因子：
3
通讯作者：
Sutoh, Kazuo
中科院分区：
文献类型：
--
作者：
Shima, Tomohiro;Imamula, Kenji;Sutoh, Kazuo
细胞质动力蛋白是一种AAA（+）型分子马达，其主要成分是两条相同的重链，包含串联的六个AAA（+）模块。它沿着单个微管在多个步骤中移动，伴随着多个ATP水解。这种进行性滑动对于体内的货物运输至关重要。为了研究细胞质动力蛋白如何表现出这种持续合成能力，我们对双头全长或截短的单头重链进行了体外运动测定。结果表明，连续微管滑动需要4 - 5个单头重链分子，而大约1个双头全长重链分子就足够了。冲程时间与总ATP酶循环时间的比率（其是持续合成能力的定量指标）对于单头重链类似于0.2，而对于全长分子类似于0.6。当两个单头重链被人工连接的卷曲螺旋的肌球蛋白，持续合成能力恢复。这些结果表明，一个单一的细胞质动力蛋白的两个头部相互沟通，采取进行步骤沿着微管。(c)2006年爱思唯尔公司All rights reserved.
Cytoplasmic dynein is an AAA(+)-type molecular motor whose major components are two identical heavy chains containing six AAA(+) modules in tandem. It moves along a single microtubule in multiple steps which are accompanied with multiple ATP hydrolysis. This processive sliding is crucial for cargo transports in vivo. To examine how cytoplasmic dynein exhibits this processivity, we performed in vitro motility assays of two-headed full-length or truncated single-headed heavy chains. The results indicated that four to five molecules of the single-headed heavy chain were required for continuous microtubule sliding, while approximately one molecule of the two-headed full-length heavy chain was enough for the continuous sliding. The ratio of the stroking time to the total ATPase cycle time, which is a quantitative indicator of the processivity, was similar to 0.2 for the single-headed heavy chain, while it was similar to 0.6 for the full-length molecule. When two single-headed heavy chains were artificially linked by a coiled-coil of myosin, the processivity was restored. These results suggest that the two heads of a single cytoplasmic dynein communicate with each other to take processive steps along a microtubule. (c) 2006 Elsevier Inc. All rights reserved.