GAP-43 expression in macroglial cells: potential functional significance.

Although growth-associated protein-43 (GAP-43) was initially considered to be neuron-specific, it has more recently been found in astrocytes, oligodendrocytes, Schwann cells, glial cell equivalents in embryonic Drosophila and other non-neuronal cells. Here I summarize evidence for the presence of GAP-43 in macroglial cells (i.e., astrocytes and oligodendrocytes) cultured from neonatal rat cortex and describe its developmental expression in a lineage-specific and cell-type-specific manner. These and other data suggest that GAP-43 is a multifunctional protein involved in the synthesis of membranes associated with the growth of various types of cellular processes, including those of macroglial cells.