A cytoskeleton-associated glycoprotein of 130-kilodalton molecular mass (GP 130) was purified from a nonionic detergent-insoluble fraction of 10-16-d-old chicken embryo brains. GP 130 is tightly associated with other proteins in actin-containing complexes (Moss, D.J., 1983, Eur. J. Biochem., 135:291-297); thus, pure protein preparations were obtained only after the partial dissociation of the complexes with the zwitterionic detergent, dimethyl dodecyl glycine (EMPIGEN BB), followed by ion-exchange chromatography and electrophoresis on preparative SDS polyacrylamide gels. Specific monoclonal and polyclonal antibodies were raised to GP 130 and used to examine its distribution in the developing nervous system. Experiments with these antibodies revealed that GP 130 is confined to nervous tissue and is restricted to the surface of neurons in cultures derived from both the central and peripheral nervous systems. This novel glycoprotein is immunologically unrelated to the neuronal cell adhesion molecule (N-CAM), or to vinculin, a protein of similar molecular mass which has been suggested to link actin filaments to the plasma membrane. In the developing chicken embryo brain, GP 130 is first detectable around day 8 after fertilization and increases to approximately 50% of its adult level by embryonal day 13. In contrast, no increase is observed over a similar developmental period in sciatic nerve. In the adult chicken, GP 130 is most abundant in brain and has a particularly high content in areas rich in dendrites and synapses.