Friday, November 8, 2013

Non-Processive Force Generation by Mammalian Axonemal Dynein In Situ on Doublet Microtubules

David P. Lorch, Kathleen A. Lesich, Charles B. Lindemann, Alan J. Hunt
We utilize optical tweezers to examine displacements produced by small numbers of dynein motors located in situ on doublet microtubules from disintegrated mammalian sperm axonemes. In contrast with cytoplasmic dynein, we find that axonemal dynein is not processive, and the duration of individual force-generating interactions with a microtubule are longer than predicted from the velocity of movements generated by large ensembles of motors. These findings suggest that tension is required for rapid release of dynein following a power stroke and may explain how axonemal dynein is adapted to work in arrays within an axoneme, where cyclical bending patterns require motors to function over a range of sliding velocities.

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