Myosin V : walking along actin without falling off ( p . 1981 )

  • Published 2001


Single motor proteins that transport cargo over long distances alone must remain attached to their cytoskeletal tracks while undergoing many productive catalytic cycles i.e. they must be processive. This is certainly true of the microtubule-based motor conventional kinesin, but what about the actin-based myosin motors? Can the deciphered kinetic schemes of the nonprocessive myosins I and II be adapted to accommodate the prolonged actin binding that a processive myosin would require? And, if so, how could such a myosin negotiate the helical actin track without becoming entangled in the cytoskeleton. Amit Mehta discusses recent single-molecule analyses, solution-kinetic experiments and structural studies of myosin V that have answered these questions. The new data indicate that myosin V is indeed a highly processive motor and has a kinetic scheme in which the rate constants of the myosin I/II scheme are tuned to favour strong actin binding. Furthermore, they reveal that myosin V takes massive (36-nm) steps along actin, which, given the 36-nm pseudorepeat of the actin helix, allow it to follow a linear rather than a helical path. Molecular models for kinetic processivity that are based on these data depart significantly from schemes proposed for other processive enzymes.

Cite this paper

@inproceedings{2001MyosinV, title={Myosin V : walking along actin without falling off ( p . 1981 )}, author={}, year={2001} }