Microtubule-associated protein-like binding of the kinesin-1 tail to microtubules.
The kinesin-1 molecular motor contains an ATP-dependent microtubule-binding site in its N-terminal head domain and an ATP-independent microtubule-binding site in its C-terminal tail domain. Here we demonstrate that a kinesin-1 tail fragment associates with microtubules with submicromolar affinity. Binding is largely electrostatic in nature, and is facilitated by a region of basic amino acids in the tail and the acidic E-hook at the C terminus of tubulin. The tail binds to a site on tubulin that is independent of the head domain-binding site but overlaps with the binding site of the microtubule-associated protein Tau. Surprisingly, the kinesin tail domain stimulates microtubule assembly and stability in a manner similar to Tau. The biological function of this strong kinesin tail-microtubule interaction remains to be seen, but it is likely to play an important role in kinesin regulation due to the close proximity of the microtubule-binding region to the conserved regulatory and cargo-binding domains of the tail.
Seeger
Mark A
MA
Department of Cell and Molecular Biology, Northwestern University, Chicago, Illinois 60611, USA.
Rice
Sarah E
SE
D000494:Allosteric Regulation; D002942:Circular Dichroism; D004563:Electrochemistry; D005454:Fluorescence Polarization; D006801:Humans; D016547:Kinesins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008854:Microscopy, Electron; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D016296:Mutagenesis; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary; D016875:tau Proteins / Q000378:metabolism
C488101:KIF5B protein, human; C054369:MAPT protein, human; D008869:Microtubule-Associated Proteins; D016875:tau Proteins; D016547:Kinesins