Single cytoplasmic dynein molecule movements: characterization and comparison with kinesin.
Cytoplasmic dynein is a major microtubule motor for minus-end directed movements including retrograde axonal transport. To better understand the mechanism by which cytoplasmic dynein converts ATP energy into motility, we have analyzed the nanometer-level displacements of latex beads coated with low numbers of cytoplasmic dynein molecules. Cytoplasmic dynein-coated beads exhibited greater lateral movements among microtubule protofilaments (ave. 5.1 times/microns of displacement) compared with kinesin (ave. 0.9 times/micron). In addition, dynein moved rearward up to 100 nm over several hundred milliseconds, often in correlation with off-axis movements from one protofilament to another. We suggest that single molecules of cytoplasmic dynein move the beads because 1) there is a linear dependence of bead motility on dynein/bead ratio, 2) the binding of beads to microtubules studied by laser tweezers is best fit by a first-order Poisson, and 3) the run length histogram of dynein beads follows a first-order decay. At the cellular level, the greater disorder of cytoplasmic dynein movements may facilitate transport by decreasing the duration of collisions between kinesin and cytoplasmic dynein-powered vesicles.
Wang
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Z
Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.
Khan
S
S
Sheetz
M P
MP
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001370:Axonal Transport / Q000502:physiology; D055592:Biophysical Phenomena; D001703:Biophysics; D002642:Chick Embryo; D003593:Cytoplasm / Q000737:chemistry* / Q000502:physiology*; D004398:Dyneins / Q000737:chemistry* / Q000502:physiology*; D004734:Energy Metabolism; D066298:In Vitro Techniques; D016547:Kinesins / Q000737:chemistry* / Q000502:physiology*; D007840:Latex; D008863:Microspheres; D009068:Movement / Q000502:physiology
D007840:Latex; D000255:Adenosine Triphosphate; D004398:Dyneins; D016547:Kinesins