Interaction of ErbB family members with Necl-2. Co-immunoprecipitation assay using HEK293 cells. Cells were co-transfected with various combinations of indicated plasmids and cultured in suspension. Each FLAG-tagged Necl family member was immunoprecipitated using the anti-FLAG mAb, and samples were subjected to Western blotting using the indicated Abs. A, assay for co-immunoprecipitation of ErbB family members with Necl-2. Aa, FLAG-Necl-2 and ErbB1; Ab, FLAG-Necl-2 and ErbB2; Ac, FLAG-Necl-2 and ErbB3; Ad, FLAG-Necl-2 and ErbB4. B, interaction of Necl-2 with ErbB3 through its extracellular region. Asterisks, full-length or mutants of Necl-2. C, assay for co-immunoprecipitation of ErbB3 with Necl family members. The results shown are representative of three independent experiments.