Of the several types of polarized cells, the neuron is one of the most dramatic examples. It extends two distinctive processes, axon and dendrite. Polarization in neurons enables the two processes to play their functionally different roles, sending and receiving electrical signals in a vectorial fashion. While a catalog of structural, molecular, and functional differences between axon and dendrite is accumulating, the mechanisms involved in establishment of neuronal polarity are not well understood. Neuronal polarity formation begins with the elongation of one process as an axon in a symmetric cell phase. In this review, we describe recent advances in the understanding of several cellular events in the early development of axon and dendrite. We also discuss the involvement of the Rho family small GTPases, their upstream and downstream molecules, and collapsin response mediator protein-2 (CRMP-2) in the regulation of neuronal polarity.
Copyright 2003 Wiley Periodicals, Inc. J Neurobiol 58: 34-47, 2004