Cell
Volume 135, Issue 6, 12 December 2008, Pages 1098-1107
Journal home page for Cell

Article
Consequences of Motor Copy Number on the Intracellular Transport of Kinesin-1-Driven Lipid Droplets

https://doi.org/10.1016/j.cell.2008.10.021Get rights and content
Under an Elsevier user license
open archive

Summary

The microtubule motor kinesin-1 plays central roles in intracellular transport. It has been widely assumed that many cellular cargos are moved by multiple kinesins and that cargos with more motors move faster and for longer distances; concrete evidence, however, is sparse. Here we rigorously test these notions using lipid droplets in Drosophila embryos. We first employ antibody inhibition, genetics, biochemistry, and particle tracking to demonstrate that kinesin-1 mediates plus-end droplet motion. We then measure how variation in kinesin-1 expression affects the forces driving individual droplets and estimate the number of kinesins actively engaged per droplet. Unlike in vitro, increased motor number results in neither longer travel distances nor higher velocities. Our data suggest that cargos in vivo can simultaneously engage multiple kinesins and that transport properties are largely unaffected by variation in motor number. Apparently, higher-order regulatory mechanisms rather than motor number per se dominate cargo transport in vivo.

CELLBIO

Cited by (0)

4

Present address: Center for Nonlinear Dynamics and Department of Physics, University of Texas at Austin, Austin, TX 78712, USA

5

Present address: Department of Biology, University of Rochester, Rochester, NY 14627, USA

6

These authors contributed equally to this work

7

These authors contributed equally to this work