Glycoconnectin (PAS 2), a membrane attachment site for the human erythrocyte cytoskeleton

The sialoglycoprotein PAS 2 is present in cytoskeletons generated by Triton X-100 extraction of isolated human erythrocyte stroma. However, removal of the peripheral cytoskeletal proteins by elution with 0.1N NaOH prior to Triton extraction renders PAS 2 Triton-soluble. This suggests association of PAS 2 with the cytoskeletal elements lining the inner surface of the erythrocyte membrane. For this reason, we are proposing the name glycoconnectin for PAS 2, since it is a glycoprotein which connects the core of the cytoskeleton to the membrane bilayer. The cytoskeletal proteins bands 4.1a,b also appear to interact directly with the membrane, since all of the other peripheral membrane proteins can be eluted with NaOH, pH 11.5, without releasing bands 4.1a,b from the membrane. Removal of spectrin and actin from the membrane results in the solubilization of both glycoconnectin and bands 4.1a,b by Triton X-100. Glycoconnectin is not present in the cytoskeletons derived from a donor whose membranes are devoid of bands 4.1a,b. These data suggest that glycoconnectin may interact directly with bands 4.1a,b.