Simultaneous Observation of the Lever Arm and Head Explains Myosin VI Dual Function
Simultaneous Observation of the Lever Arm and Head Explains Myosin VI Dual Function
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DOI：
10.1002/smll.201200765
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发表时间：
2012-10-08
期刊：
影响因子：
13.3
通讯作者：
Yanagida, Toshio
中科院分区：
文献类型：
--
作者：
Ikezaki, Keigo;Komori, Tomotaka;Yanagida, Toshio
肌球蛋白VI是由三磷酸腺苷（ATP）驱动的二聚体分子马达，具有囊泡转运体和细胞骨架锚的双重功能。最近，据报道，肌球蛋白VI产生三种类型的步骤，通过采取一个遥远的结合或相邻的结合状态（非经典的手在手的步骤途径）。相邻的结合状态，其中两个头部结合到一个肌动蛋白丝附近的另一个，是独特的肌球蛋白VI，因此可能有助于解释其独特的功能。然而，相邻结合状态的详细信息仍不清楚。在这里，同时观察的头部和尾部域在步进。这些观察结果表明，在相邻的结合状态下，杠杆臂向前倾斜。此外，它表明，任何头部可以采取后续步骤，从这个状态具有相同的概率。与以前的结果一起，提出了一个全面的步进计划，它包括尾域运动来解释肌球蛋白VI如何实现其双重功能。
Myosin VI is an adenosine triphosphate (ATP)-driven dimeric molecular motor that has dual function as a vesicle transporter and a cytoskeletal anchor. Recently, it was reported that myosin VI generates three types of steps by taking either a distant binding or adjacent binding state (noncanonical hand-over-hand step pathway). The adjacent binding state, in which both heads bind to an actin filament near one another, is unique to myosin VI and therefore may help explain its distinct features. However, detailed information of the adjacent binding state remains unclear. Here simultaneous observations of the head and tail domain during stepping are presented. These observations show that the lever arms tilt forward in the adjacent binding state. Furthermore, it is revealed that either head could take the subsequent step with equal probability from this state. Together with previous results, a comprehensive stepping scheme is proposed; it includes the tail domain motion to explain how myosin VI achieves its dual function.