This Article Full Text Full Text (PDF) Supplement All Versions of this Article: biophysj.105.076265v1 91/4/1407    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Jaud, J. Articles by Woehlke, G. Search for Related Content PubMed PubMed Citation Articles by Jaud, J. Articles by Woehlke, G.

Flexibility of the Neck Domain Enhances Kinesin-1 Motility under Load

Johann Jaud ^*, Friederike Bathe , Manfred Schliwa , Matthias Rief ^* and Günther Woehlke 

^* Physics Department E22, Technical University Munich, Garching, Germany; and Institute for Cell Biology, University of Munich, Munich, Germany

Correspondence: Address reprint requests to Günther Woehlke, Tel.: 49-89-2180-75889; Fax: 49-89-2180-75882; E-mail: guenther.woehlke{at}lrz.uni-muenchen.de.

Kinesin-1 is a dimeric motor protein that moves stepwise along microtubules. A two-stranded -helical coiled-coil formed by the neck domain links the two heads of the molecule, and forces the motor heads to alternate. By exchanging the particularly soft neck region of the conventional kinesin from the fungus Neurospora crassa with an artificial, highly stable coiled-coil we investigated how this domain affects motor kinetics and motility. Under unloaded standard conditions, both motor constructs developed the same gliding velocity. However, in a force-feedback laser trap the mutant showed increasing motility defects with increasing loads, and did not reach wild-type velocities and run lengths. The stall force dropped significantly from 4.1 to 3.0 pN. These results indicate the compliance of kinesin's neck is important to sustain motility under load, and reveal a so far unknown constrain on the imperfect coiled-coil heptad pattern of Kinesin-1. We conclude that coiled-coil structures, a motif encountered in various types of molecular motors, are not merely a clamp for linking two heavy chains to a functional unit but may have specifically evolved to allow motor progression in a viscous, inhomogeneous environment or when several motors attached to a transported vesicle are required to cooperate efficiently.

This article has been cited by other articles:

				A. H. Crevenna, S. Madathil, D. N. Cohen, M. Wagenbach, K. Fahmy, and J. Howard Secondary Structure and Compliance of a Predicted Flexible Domain in Kinesin-1 Necessary for Cooperation of Motors Biophys. J., December 1, 2008; 95(11): 5216 - 5227. [Abstract] [Full Text] [PDF]

				B. Ebbing, K. Mann, A. Starosta, J. Jaud, L. Schols, R. Schule, and G. Woehlke Effect of spastic paraplegia mutations in KIF5A kinesin on transport activity Hum. Mol. Genet., May 1, 2008; 17(9): 1245 - 1252. [Abstract] [Full Text] [PDF]