Neural cell adhesion molecule mediates initial interactions between spinal cord neurons and muscle cells in culture.

Abstract

Previous studies have described a cell surface glycoprotein, called neural cell adhesion molecule or N-CAM, that appears to be a ligand in the adhesion between neural membranes. N-CAM antigenic determinants were shown to be present on embryonic muscle and an N-CAM-dependent adhesion was demonstrated between retinal cell membranes and muscle cells in short-term assays. These antigenic determinants are apparently associated with the N-CAM polypeptide, and rapid adhesion mediated by this molecule occurs between [chick embryo] spinal cord membranes and muscle cells. Detailed examination of the effects of anti-(N-CAM) Fab'' fragments in cultures of spinal cord with skeletal muscle showed that the Fab'' fragments specifically block adhesion of spinal cord neurites and cells to myotubes. The Fab'' did not affect binding of neurites to fibroblasts and collagen substrate and did not alter myotube morphology. N-CAM adhesion is essential for the in vitro establishment of physical associations between nerve and muscle. Binding involving N-CAM may be an important early step in synaptogenesis.