Single-headed mode of kinesin-5.
In most organisms, kinesin-5 motors are essential for mitosis and meiosis, where they crosslink and slide apart the antiparallel microtubule half-spindles. Recently, it was shown using single-molecule optical trapping that a truncated, double-headed human kinesin-5 dimer can step processively along microtubules. However, processivity is limited ( approximately 8 steps) with little coordination between the heads, raising the possibility that kinesin-5 motors might also be able to move by a nonprocessive mechanism. To investigate this, we engineered single-headed kinesin-5 dimers. We show that a set of these single-headed Eg5 dimers drive microtubule sliding at about 90% of wild-type velocity, indicating that Eg5 can slide microtubules by a mechanism in which one head of each Eg5 head-pair is effectively redundant. On the basis of this, we propose a muscle-like model for Eg5-driven microtubule sliding in spindles in which most force-generating events are single-headed interactions and alternate-heads processivity is rare.
Molecular Motors Group, Marie Curie Research Institute, The Chart, Oxted, Surrey RH8 0TL, UK.
Kuniyoshi
K
Kaseda
Isabelle
I
Crevel
Keiko
K
Hirose
Robert A
RA
Cross
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D019281:Dimerization; D004591:Electrophoresis, Polyacrylamide Gel; D016547:Kinesins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D008870:Microtubules / Q000502:physiology*; D008954:Models, Biological; D029867:Xenopus Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D014982:Xenopus laevis
D029867:Xenopus Proteins; D000251:Adenosine Triphosphatases; D016547:Kinesins