Figure 1.

Analysis of PTK7-binding domains of anti-PTK7 mAbs. (A) Diagrams of PTK7 and its deletion mutants (PTK7-Ig1-7-His also called sPTK7, PTK7-Ig1-5-His, PTK7-Ig1-4-His, PTK7-Ig1-3-His, PTK7-Ig2-4-His, and PTK7-Ig3-4-His) are shown. SP, signal peptide; Ext, extracellular region including 7 Ig domains; TM, transmembrane domain; Cyt, cytosolic region containing a catalytically defective catalytic tyrosine kinase domain (indicated as Defective TK); and H₆, His tag. (B) Results of the pull-down assay to determine the PTK7-binding domains of mAb-32, mAb-43, mAb-50, and mAb-52. PTK7-Ig1-7-His and its deletion mutants were incubated with anti-PTK7 mAbs at a 1:1 molar ratio. Proteins pulled down with Ni²⁺-NTA agarose resins were subjected to SDS-PAGE and Western blotting with anti-His antibodies.