Fig. 4

Sequence of some identified partners of band 4.1/JEF domains. (A) The sequence of glycophorin C necessary and sufficient for binding band 4.1 has been defined (21,22) (underlined). Drosophila neurexin IV binds Coracle (38) and rat paranodin binds band 4.1-related proteins (35). Conserved residues between these three proteins define a GNP motif that was found in several proteins or open reading frames by BLAST 2 analysis, using the intracellular domain of glycophorin C, neurexin IV, or paranodin as queries. Neurexins I–III, which have a related, albeit less conserved sequence, have also been proposed to be band 4.1 ligands (39). Residues identical in the proteins of the GNP group are white on black background (conserved in the three proteins) or gray background (conserved in two proteins). Similar residues are black on light gray background. The conserved motif at the C terminus of several of these proteins is not part of the GNP motif but is a proven or potential binding site for PDZ domains. Accession numbers: human glycophorin C: P04921; Drosophila neurexin IV: AF039833; rat paranodin: AF000114; mouse B12: AF061260; human F22162_1:AC005525; human CD46: 1708 964; CET01G9.3: Z75713; rat neurexins (NRX): I-α, A40228; II-α, C40228; III-α, L14851. (B) Other ligands of band 4.1/JEF domains include CD44, CD43, and ICAM-2 (47) for ERM proteins, band 3 (25) and p55 for band 4.1 (21), and β integrins cytoplasmic tail for FAK (100). Sequences shown to be important for binding in the references are underlined. Clusters of basic residues are in boldface. Accession numbers: Mouse CD44: X66081; rat CD43: PI3838; human ICAM-2: X65490; human band 3 anion exchange protein 1: P02730; human p55: M64925; human integrins: α1, P05556; α32 825636; α3, P05106.