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Myosin V from Drosophila reveals diversity of motor mechanisms within the myosin V family
被引:39
|作者:
Tóth, J
Kovács, M
Wang, F
Nyitray, L
Sellers, JR
机构:
[1] NHLBI, Lab Mol Physiol, NIH, Bethesda, MD 20892 USA
[2] Eotvos Lorand Univ, Dept Biochem, H-1117 Budapest, Hungary
关键词:
D O I:
10.1074/jbc.M505209200
中图分类号:
Q5 [生物化学];
Q7 [分子生物学];
学科分类号:
071010 ;
081704 ;
摘要:
Myosin V is the best characterized vesicle transporter in vertebrates, but it has been unknown as to whether all members of the myosin V family share a common, evolutionarily conserved mechanism of action. Here we show that myosin V from Drosophila has a strikingly different motor mechanism from that of vertebrate myosin Va, and it is a nonprocessive, ensemble motor. Our steady-state and transient kinetic measurements on single-headed constructs reveal that a single Drosophila myosin V molecule spends most of its mechanochemical cycle time detached from actin, therefore it has to function in processive units that comprise several molecules. Accordingly, in in vitro motility assays, double-headed Drosophila myosin V requires high surface concentrations to exhibit a continuous translocation of actin filaments. Our comparison between vertebrate and fly myosin V demonstrates that the well preserved function of myosin V motors in cytoplasmic transport can be accomplished by markedly different underlying mechanisms.
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页码:30594 / 30603
页数:10
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