The role of the exocyst complex in neural cell adhesion molecule mediated morphogenesis in Mus musculus (Linnaeus, 1758)

Abstract

The exocyst complex is required for polarized exocytosis in a variety of cells being involved in morphogenesis of neurons. We show that it binds to the intracellular domain of the neural cell adhesion molecule NCAM and this binding is enhanced in response to ligand-induced clustering of NCAM at the cell surface. NCAM promotes FGF receptor-mediated tyrosine phosphorylation of the exocyst complex and is required for its efficient recruitment to growth cones. Clustering of NCAM at the surface of growth cones induces Ca2+ dependent vesicle exocytosis which is blocked by an inhibitor of L-type voltage dependent Ca2+ channels. NCAM deficiency results in reduced tethering of the trans-Golgi network (TGN) derived organelles near the leading edge of growth cones and abnormal accumulation of the TGN derived organelles in growth cones and neurites. Thus, we reveal a novel role for a cell adhesion molecule in that it regulates addition of the new membrane to the cell surface of growth cones in developing neurons.