Lpd directly interacts with the SH3 domain of Abi. (A) Pull-down of Lpd from NIH/3T3 cell lysate using the GST-Abi-SH3 domain or GST as control. (B–D) Far Western overlay on different GST-Lpd truncation mutants (B) or GST control using purified (C) MBP-Abi1^full-length or (D) MBP-Abi1^ΔSH3 was detected with anti-MBP antibodies. Three independent experiments were performed. (E) Far-Western overlay with MBP-Abi1^full-length on a peptide array covering the C terminus of Lpd with 12-mer peptides overlapping each other by three amino acids was detected with anti-MBP antibodies. (F) Table shows Abi SH3 domain–binding motifs in the Lpd sequence. The two GST-Lpd fragments highlighted in red correspond to the most strongly interacting Lpd fragments in the Far-Western experiment in C. The amino acid residues highlighted in yellow correspond to the core residues required for class II SH3 domain binding.