Single-molecule analysis of kinesin motility reveals regulation by the cargo-binding tail domain

Nat Cell Biol. 1999 Sep;1(5):293-7. doi: 10.1038/13008.


Conventional kinesin transports membranes along microtubules in vivo, but the majority of cellular kinesin is unattached to cargo. The motility of non-cargo-bound, soluble kinesin may be repressed by an interaction between the amino-terminal motor and carboxy-terminal cargo-binding tail domains, but neither bead nor microtubule-gliding assays have shown such inhibition. Here we use a single-molecule assay that measures the motility of kinesin unattached to a surface. We show that full-length kinesin binds microtubules and moves about ten times less frequently and exhibits discontinuous motion compared with a truncated kinesin lacking a tail. Mutation of either the stalk hinge or neck coiled-coil domain activates motility of full-length kinesin, indicating that these regions are important for tail-mediated repression. Our results suggest that the motility of soluble kinesin in the cell is inhibited and that the motor becomes activated by cargo binding.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Amino Acid Substitution
  • Animals
  • Cell Line
  • Kinesins / chemistry*
  • Kinesins / genetics
  • Kinesins / physiology*
  • Microtubules / physiology*
  • Molecular Sequence Data
  • Movement
  • Mutagenesis, Site-Directed
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Spodoptera
  • Transfection


  • Recombinant Proteins
  • Kinesins

Associated data

  • GENBANK/L04733
  • GENBANK/U06698