Kinesin Walks the Line: Single Motors Observed by Atomic Force Microscopy

Motor proteins of the kinesin family move actively along microtubules to transport cargo within cells. How exactly a single motor proceeds on the 13 narrow lanes or protofilaments of a microtubule has not been visualized directly, and there persists controversy on the relative position of the two ki...

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Bibliographic Details
Published in:Biophysical journal 2011-05, Vol.100 (10), p.2450-2456
Main Authors: Schaap, Iwan A.T., Carrasco, Carolina, de Pablo, Pedro J., Schmidt, Christoph F.
Format: Article
Language:English
Subjects:
Actin Cytoskeleton - drug effects
Actin Cytoskeleton - metabolism
adenosine triphosphate
Adenosine Triphosphate - pharmacology
Adenylyl Imidodiphosphate - pharmacology
Atomic force microscopy
ATP
Binding sites
Biophysics
Cells
Computer Simulation
Cytoskeleton
Dimers
Humans
image analysis
Imaging
Immobilized Proteins - metabolism
kinesin
Kinesin - chemistry
Kinesin - metabolism
Microscopy
Microscopy, Atomic Force - methods
microtubules
Microtubules - drug effects
Microtubules - metabolism
molecular motor proteins
Motors
Muscle, Motility, and Motor Protein
Neurospora crassa - drug effects
Neurospora crassa - metabolism
Nucleotides
Physiology
Protein Binding - drug effects
Protein Multimerization - drug effects
Protein Transport - drug effects
Proteins
Transport
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Description
Summary:Motor proteins of the kinesin family move actively along microtubules to transport cargo within cells. How exactly a single motor proceeds on the 13 narrow lanes or protofilaments of a microtubule has not been visualized directly, and there persists controversy on the relative position of the two kinesin heads in different nucleotide states. We have succeeded in imaging Kinesin-1 dimers immobilized on microtubules with single-head resolution by atomic force microscopy. Moreover, we could catch glimpses of single Kinesin-1 dimers in their motion along microtubules with nanometer resolution. We find in our experiments that frequently both heads of one dimer are microtubule-bound at submicromolar ATP concentrations. Furthermore, we could unambiguously resolve that both heads bind to the same protofilament, instead of straddling two, and remain on this track during processive movement.
ISSN:0006-3495
1542-0086
DOI:10.1016/j.bpj.2011.04.015