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Simultaneous Observation of the Lever Arm and Head Explains Myosin VI Dual Function
Author(s) -
Ikezaki Keigo,
Komori Tomotaka,
Sugawa Mitsuhiro,
Arai Yoshiyuki,
Nishikawa So,
Iwane Atsuko H.,
Yanagida Toshio
Publication year - 2012
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201200765
Subject(s) - myosin , myosin head , molecular motor , actin , biophysics , adenosine triphosphate , binding domain , protein filament , cytoskeleton , domain (mathematical analysis) , function (biology) , chemistry , physics , binding site , microbiology and biotechnology , myosin light chain kinase , biology , biochemistry , mathematics , cell , mathematical analysis
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.