Heterophilic interactions of the neural cell adhesion molecules Ng-CAM and Nr-CAM with neural receptors and extracellular matrix proteins

Ng-CAM/L1 and Nr-CAM are closely related neural cell adhesion molecules expressed on neurons and Schwann cells. Ng-CAM/L1 is prevalent on axons and is a potent promoter of neurite growth and axonal fasciculation. Although Nr-CAM does not appear to play a major role in these functions, its transient expression in the developing floor plate of the spinal cord is important for guidance of commissural axons. Ng-CAM and Nr-CAM can bind homophilicly and heterophilicly to several adhesion molecules. Different complexes of adhesion molecules are likely to control axonal growth and guidance as a consequence of their differential localizations in vivo.