DIVERSE FUNCTIONS OF THE EXTRACELLULAR-MATRIX MOLECULE AGRIN

The extracellular matrix is a well organized structure with profound e ffects on the development and the integrity of adherent tissues. Again is a component of many matrices, such as the basement membrane of kid ney, blood capillaries and the muscle fiber basal lamina, where it is highly concentrated at the neuromuscular junction. During synapse form ation agrin is believed to promote differentiation of the postsynaptic muscle fibers and the presynaptic motor neuron. This complex process is, at least in part, based on specific interactions of again with oth er matrix molecules and with membrane-associated or integral membrane proteins of the abutting cells. This review summarizes studies concern ing the interaction of agrin with other molecules and highlights possi ble functions of agrin in the synaptic basal lamina and in other matri ces.