Cellular Mechanisms for the Axonal Pattern Formation: Initiation and Branch Morphogenesis

The establishment and maintenance of characteristic cellular morphology is especially important in the nervous system, in which neurons make connections with specific targets, thereby enabling the processing of information. The axonal pattern is crucial in determining the target cells, and is controlled by extracellular molecules, called axon guidance molecules. In culture, isolated neurons are capable of extending the axon and establishing mature neuronal morphology without particular cell-extrinsic cues. Molecular systems that control this cell-autonomous process remain to be elucidated. In this paper, we summarize the cellular processes of axonal patterning and some of the intracellular molecular mechanisms that contribute to maintain the axon morphology.