Force–velocity relationship for multiple kinesin motors pulling a magnetic bead

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 a...

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Bibliographic Details
Published in:European biophysics journal 2011-09, Vol.40 (9), p.1071-1079
Main Authors: Fallesen, Todd L., Macosko, Jed C., Holzwarth, G.
Format: Article
Language:English
Subjects:
Animals
Bioassays
Biochemistry
Biological and Medical Physics
Biomechanical Phenomena
Biomedical and Life Sciences
Biophysics
Biotin - metabolism
Cattle
Cell Biology
Drosophila Proteins - metabolism
Eukaryotes
Kinesin - metabolism
Kinetics
Life Sciences
Magnetic Fields
Mechanical Phenomena
Membrane Biology
Microspheres
Microtubules - metabolism
Nanotechnology
Neurobiology
Original Paper
Proteins
Streptavidin - metabolism
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Summary: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 〈 n 〉, 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)].
ISSN:0175-7571
1432-1017
DOI:10.1007/s00249-011-0724-1