Kinesin, dynein and neurofilament transport

The recent demonstration that the fast axonal transport motors kinesin and dynein participate in axonal transport of neurofilaments-known to undergo s low transport-supports and extends recent studies indicating that some neur ofilaments exhibit alternating bursts of fast axonal transport interspersed with periods of non-motility. In addition, these findings unify both certa in aspects of axonal transport and neurofilament biology. We discuss these data herein in the context of both older and more recent studies of neurofi lament dynamics.