Studies of proteins specific to a certain type of cell are of general interest because these proteins may be involved in the determination of morphological and functional characteristics of the cell. In the nervous tissue, many "neuron-specific" and "glia-specific" proteins have been identified by various biochemical and immunohistochemical means and their relationships to cell functions have been studied. This paper briefly reviews our studies on the chemical and cell-biological aspects of the neuron- and glia-specific proteins, with special reference to the 14-3-3 protein and the S100 protein. Our studies suggest that glial protein S100 may be involved in the regulation of cell growth and differentiation, while neuronal protein 14-3-3, in the regulation of serotonin and catecholamine biosynthesis in neurons and other monoamine-synthesizing cells.