Binding of recombinant spectrin fragments and spectrin single repeats to Lu(v13) and Lu. (A) Schematic presentation of recombinant spectrin fragments. The boundaries of all spectrin fragments and single repeats were defined by SMART annotations. (B) Nine GST-tagged spectrin fragments were incubated with biotin-labeled Lu(v13) peptide, and binding was detected with anti-GST antibody. Only α N-5 was brought down. (C) The GST-tagged single repeats within α N-5 fragment were incubated with biotin-labeled Lu(v13) peptide, and the binding was detected as described for panel B. Only αR4 was brought down. (D) The His-tagged single repeats were incubated with GST-tagged cytoplasmic domain of Lu, and the binding was detected with anti-His antibody. Only αR4 was brought down.