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#kinesin-1

3 public questions tagged with this topic.

Cytoskeleton

What regulates kinesin-1 activation?

Kinesin-1 regulation avoids gratuitous ATP consumption and traffic jams by autoinhibition mechanism evolutionarily conserved ensuring motor only active when bound to cargo. In cargo free state heavy chain tail IAK motif folds back contacting motor head switch regions blocking microtubule stimulated ADP release maintaining ATPase low about 10 fold inhibition. Light chains also contribute to folded globular conformation compact. Cargo adaptors such as JNK interacting proteins JIP1-3 FEZ1 Milton TRAK bind light chains or tail sterically unfolding molecule to extended active state increasing micro

Ref: Verhey & Hammond, Nat Rev Mol Cell Biol 2009 – Kinesin-1 activation by cargo binding unfolding mechanism.

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Cytoskeleton

The stalk domain of kinesin-1 is responsible for:

Domain architecture of kinesin-1 reveals clear division of labor essential for processive dimer motor function. N terminal globular motor domain about 340 amino acids contains P loop ATPase site switch I II microtubule binding interface and neck linker for mechanochemistry converting ATP hydrolysis to mechanical step. Immediately C terminal lies neck coiled coil ensuring dimerization of motor domains upon folding critical for hand over hand coordination followed by elongated stalk extending about 50 nm formed by interrupted coiled coil heptad repeats left handed supercoils stabilizing heavy ch

Ref: Hirokawa & Noda, Physiol Rev 2008 – Kinesin-1 stalk coiled coil mediated dimerization domain function.

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Cytoskeleton

How does kinesin-1 move along microtubules?

Kinesin-1 conventional motor transports cargo over long distances toward plus ends at velocities up to 1 micron per second. Heavy chain dimerization produces two motor heads coordinated via neck linker docking mechanism. Motility described as processive sliding or walking because motor maintains continuous association via at least one head bound at any moment preventing diffusion away from track essential for long range transport. ATP binding to leading head causes neck linker zipping toward plus end throwing lagging head forward to next binding site 8 nm ahead matching tubulin dimer repeat an

Ref: Vale & Fletterick, Annu Rev Cell Dev Biol – Kinesin-1 sliding walking mechanism along microtubules processivity.

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