MEMBRANE ATTACHMENT PROTEIN FOR SPECTRIN IS ASSOCIATED WITH BAND-3 IN HUMAN-ERYTHROCYTE MEMBRANES

Ankyrin, the membrane attachment protein for human erythrocyte spectrin,is tightly linked in a 1:1 molar ratio with band 3 in detergent extracts of spectrin-depleted membranes.Ankyrin-linked band 3,which represents 10-15% of the total band 3,spans the membrane,and is nearly identical to the major band 3 by peptide analysis.Spectrin binds to solubilised ankyrin-linked band 3,but not to free band 3.A portion of band 3 remains firmly associated with detergent-extracted cytoskeletal proteins.It is concluded that a fraction of band 3 is attached to the erythrocyte cytoskeleton through association with ankyrin,which in turn is bound to spectrin. © 1979 Nature Publishing Group.