GSK319197A binds to GPR55, but not to the CB1 receptor. Competition binding experiments were performed with 1.25 nm [3H]SR141716A as a tracer on HEK293 (A), HEK-CB1 (B), HEK-GPR55 (C), and HEK-GPR55+CB1 (D) membranes in the presence of increasing concentrations of SR141716A (■) or GSK319197A (▴). Experiments were performed in duplicates, data are mean ± S.E.