DDR1 is potently inhibited by nilotinib and dasatinib. (A) DDR1 wild-type (wt) and a kinase-inactive variant (K655M) were overexpressed in HEK293 cells and left untreated or treated for 1 hour with 1 μM dasatinib. Total cell lysates were immunoblotted with anti-DDR1 and antiphosphotyrosine antibodies. (B) DDR1 was overexpressed in HEK293 cells and treated for 1 hour with the indicated concentrations of dasatinib and nilotinib. Immunoprecipitated DDR1 was immunoblotted in parallel with anti-DDR1 and antiphosphotyrosine antibodies. (C) Sequence alignment of human ABL and human DDR1. All residues that are contacted by dasatinib are indicated by boxes and conserved among the 2 kinases. The lysine residue that is mutated in the kinase-inactive DDR1 variant K655M is indicated by gray shading.