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Elife. 2014 Sep 10;3:e03680. doi: 10.7554/eLife.03680.

Conserved mechanisms of microtubule-stimulated ADP release, ATP binding, and force generation in transport kinesins.

Author information

1
Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, University of London, London, United Kingdom.
2
Structural Motility, Institut Curie, Centre National de la Recherche Scientifique, Paris, France.
3
Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, United States.

Abstract

Kinesins are a superfamily of microtubule-based ATP-powered motors, important for multiple, essential cellular functions. How microtubule binding stimulates their ATPase and controls force generation is not understood. To address this fundamental question, we visualized microtubule-bound kinesin-1 and kinesin-3 motor domains at multiple steps in their ATPase cycles--including their nucleotide-free states--at ∼ 7 Å resolution using cryo-electron microscopy. In both motors, microtubule binding promotes ordered conformations of conserved loops that stimulate ADP release, enhance microtubule affinity and prime the catalytic site for ATP binding. ATP binding causes only small shifts of these nucleotide-coordinating loops but induces large conformational changes elsewhere that allow force generation and neck linker docking towards the microtubule plus end. Family-specific differences across the kinesin-microtubule interface account for the distinctive properties of each motor. Our data thus provide evidence for a conserved ATP-driven mechanism for kinesins and reveal the critical mechanistic contribution of the microtubule interface.

KEYWORDS:

ATPase; biophysics; cryo-electron microscopy; cytoskeleton; human; kinesin; microtubule; motor; structural biology

PMID:
25209998
PMCID:
PMC4358365
DOI:
10.7554/eLife.03680
[Indexed for MEDLINE]
Free PMC Article

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