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

George T. Shubeita, Susan L. Tran, Jing Xu, Michael Vershinin, Silvia Cermelli, Sean L. Cotton, Michael A. Welte, Steven P. Gross

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish (US)
Pages (from-to)1098-1107
Number of pages10
Issue number6
StatePublished - Dec 12 2008



ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology


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