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          Institute: MPI für molekulare Zellbiologie und Genetik     Collection: Publikationen MPI-CBG 2007     Display Documents



ID: 348578.0, MPI für molekulare Zellbiologie und Genetik / Publikationen MPI-CBG 2007
Detection of fractional steps in cargo movement by the collective operation of kinesin-1 motors
Authors:Leduc, Cecile; Ruhnow, Felix; Howard, Jonathon; Diez, Stefan
Date of Publication (YYYY-MM-DD):2007
Title of Journal:Proceedings of the National Academy of Sciences of the United States of America
Volume:104
Issue / Number:26
Start Page:10847
End Page:10852
Copyright:not available
Audience:Experts Only
Intended Educational Use:No
Abstract / Description:The stepping behavior of single kinesin-1 motor proteins has been studied in great detail. However, in cells, these motors often do not work alone but rather function in small groups when they transport cellular cargo. Until now, the cooperative interactions between motors in such groups were poorly understood. A fundamental question is whether two or more motors that move the same cargo step in synchrony, producing the same step size as a single motor, or whether the step size of the cargo movement varies. To answer this question, we performed in vitro gliding motility assays, where microtubules coated with quantum dots were driven over a glass surface by a known number of kinesin-1 motors. The motion of individual microtubules was then tracked with nanometer precision. In the case of transport by two kinesin-1 motors, we found successive 4-nm steps, corresponding to half the step size of a single motor. Dwell-time analysis did not reveal any coordination, in the sense of alternate stepping, between the motors. When three motors interacted in collective transport, we identified distinct forward and backward jumps on the order of 10 nm. The existence of the fractional steps as well as the distinct jumps illustrate a lack of synchronization and has implications for the analysis of motor-driven organelle movement investigated in vivo.
External Publication Status:published
Document Type:Article
Communicated by:n. n.
Affiliations:MPI für molekulare Zellbiologie und Genetik
Identifiers:LOCALID:843
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