title: Force-velocity relationship for multiple kinesin motors pulling a magnetic bead.
abstract: Although the velocity of single kinesin motors against an opposing force F of 0-10 pN is well known, the behavior of multiple kinesin motors working to overcome a larger load is still poorly understood. We have carried out gliding assays in which 3-7 Drosophila kinesin-1 motors moved a microtubule at 200-700 μm/s against a 0-31 pN load at saturating [ATP]. The load F was generated by applying a spatially uniform magnetic field gradient to a superparamagnetic bead attached to the (+) end of the microtubule. When F was scaled by the average number of motors [Symbol: see text]n[Symbol: see text], the force-velocity relationship for multiple motors was similar to the force-velocity relationship for a single motor, supporting a minimal load-sharing model. The velocity distribution at low load has a single mode consistent with rapid fluctuations of n. However, against a load of 2.5-4.7 pN/motor, additional modes appeared at lower velocity. These observations support the Klumpp-Lipowsky model of multimotor transport [Proc Natl Acad Sci USA 102. 17284-17289 (2005)].
authors: Department of Physics, Wake Forest University, PO Box 7507, Winston-Salem, NC 27109, USA.
authors: Todd L
authors: TL
authors: Fallesen
authors: Jed C
authors: JC
authors: Macosko
authors: G
authors: G
authors: Holzwarth
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001710:Biotin / Q000378:metabolism; D002417:Cattle; D029721:Drosophila Proteins / Q000378:metabolism*; D016547:Kinesins / Q000378:metabolism*; D007700:Kinetics; D060526:Magnetic Fields; D055595:Mechanical Phenomena; D008863:Microspheres; D008870:Microtubules / Q000378:metabolism; D019809:Streptavidin / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D001710:Biotin; D019809:Streptavidin; D016547:Kinesins