A mutant of the motor protein kinesin that moves in both directions on microtubules.

Journal Article (Journal Article)

Molecular motors move directionally to either the plus or the minus end of microtubules or actin filaments. Kinesin moves towards microtubule plus ends, whereas the kinesin-related Ncd motor moves to the minus ends. The 'neck'--the region between the stalk and motor domain--is required for Ncd to move to microtubule minus ends, but the mechanism underlying directional motor movement is not understood. Here we show that a single amino-acid change in the Ncd neck causes the motor to reverse directions and move with wild-type velocities towards the plus or minus end; thus, the neck is functional but directionality is defective. Mutation of a motor-core residue that touches the neck residue in crystal structures also results in movement in both directions, indicating that directed movement to the minus end requires interactions of the neck and motor core. Low-density laser-trap assays show that a conformational change or working stroke of the Ncd motor is directional and biased towards the minus end, whereas that of the neck mutant occurs in either direction. We conclude that the directional bias of the working stroke is dependent on neck/motor core interactions. Absence of these interactions removes directional constraints and permits movement in either direction.

Full Text

Duke Authors

Cited Authors

  • Endow, SA; Higuchi, H

Published Date

  • August 24, 2000

Published In

Volume / Issue

  • 406 / 6798

Start / End Page

  • 913 - 916

PubMed ID

  • 10972296

International Standard Serial Number (ISSN)

  • 0028-0836

Digital Object Identifier (DOI)

  • 10.1038/35022617


  • eng

Conference Location

  • England