Identification of spinal cord polypeptides related to glial fibrillary acidic protein (GFAP)

Spinal cord cytoskeletal preparations from three different mammalian species contain several polypeptides in the SDS-PAGE molecular weight range 100-220 kDa which are recognized by all members of a panel of antibodies to glial fibrillary acidic protein (GFAP) and by anti-IFA, a panspecific intermediate filament protein antibody. The polypeptides are not recognized by antibodies to other intermediate filament proteins or to ubiquitin. The proteins coelute with GFAP in ion-exchange chromatography, cosediment with GFAP under filament assembly conditions, produce similar chemical digest patterns and have an amino acid profile close to that of pure GFAP, all properties expected for covalent GFAP multimers. Further experiments provide evidence for the existence of such multimeric complexes in vivo.