FIGURE 2.

The LKEX₄E motif mediates CtIP dimer formation. A, the N terminus of human CtIP is aligned with CtIP from other indicated species including CtIP yeast homologue Sae2 (S. cerevisiae), with black boxes indicating conserved residues. B, 293T cells were co-transfected with Myc-CtIP 1–897 and HA-CtIP 1–897 or the indicated mutants: CtIP 20–45del (amino acids 20–45 deleted) and CtIP LKEX₄Emut (conserved residues Leu-27 mutated to proline, and Lys-28, Glu-29, and Glu-34 mutated to alanine). Anti-Myc IP was performed, followed by anti-HA Western blotting. IP, immunoprecipitation.