Processive and nonprocessive models of kinesin movement

Conventional kinesin is the prototypic member of a family of diverse proteins that use the chemical energy of AT? hydrolysis to generate force and move along microtubules. These proteins, which are involved in a wide range of cellular functions, have been identified in protozoa, fungi, plants, and animals and possess it high degree of sequence conservation among species in their motor domains. The biochemical properties of kinesin and its homologues, in conjunction with the recently solved three-dimensional structures of several kinesin motors, have contributed to our understanding of the mechanism of kinesin movement along microtubules. We discuss several models for movement, including the hand-over-hand, inchworm, and biased diffusion models of processive movement, as well as models of nonprocessive movement.