Goblin, a high molecular weight (Mr, 260,000) polypeptide of avian erythrocyte plasma membranes characterized by hormone-dependent phosphorylation, is shown by a variety of criteria to be the avian equivalent of ankyrin, the membrane attachment protein for spectrin; a polyclonal monospecific goblin antiserum reacts specifically with ankyrin from mammalian erythrocyte ghosts; goblin and ankyrin have highly homologous, although distinct, two-dimensional peptide maps; and, in reconstitution experiments, goblin binds to spectrin and band 3 in approximately the same molar ratio as ankyrin. Immunoautoradiography and immunofluorescence with goblin antiserum reveal that a serologically related polypeptide Mr, 235,000) is present in highly purified ...