Extracellular matrix molecules and their receptors: functions in neural development.

The development of neurons and virtually all other cell types in the organism depends upon interactions with molecules in their environment. Studies of individual cell types have revealed tremendous diversity in the molecules that regulate the development of cells in the nervous system. These include chemotropic and trophic factors [e.g. nerve growth-factor (NGF) and brain derived neurotrophic factor (BDNF)], cell adhesion molecules [e.g. the neural cell adhesion molecule (NCAM) and N-cadherin], and molecules secreted into the extracellular matrix (ECM) [e.g. laminin (LN) and fibronectin (FN)]. Each class of molecule has now been shown influence major steps in the development of the nervous system, including neuronal survival, determination, and migration; axonal growth and guidance; synapse tbrmation; and glial differentiation. As molecules in the