The role of microtubule polarity in the movement of kinesin and kinetochores.

Microtubules are important for organizing and directing many types of intracellular motility. Recently progress has been made in the analysis of two types of motility at the molecular level: the movement of axonal vesicles driven by kinesin, and the movement of chromosomes driven by the kinetochore. Both require ATP for movement in vitro. Kinesin-driven movement is unidirectional, towards the microtubule plus end, while movement of the kinetochore is bidirectional. These similarities and differences are discussed and incorporated into a new model for the kinetochore-microtubule interface.