CD147 and RAP2 interaction. (A) The full length of the RAP2 protein sequence with mass spectrometry–identified peptide sequences highlighted in red. (B) Western blots showing Co-IP of CD147 and RAP2 overexpressed in HEK-293 cells. CD147 is HIS-tagged and RAP2 is FLAG-tagged. Reciprocal pull-down and detection results are shown. (C) Western blots showing Co-IP of CD147 and RAP2 protein purified from Escherichia coli. Reciprocal Co-IP and detection results are shown. (D) The binding affinity of RAP2 to CD147 by SPR. The calculated K_D value is shown as mean ± standard deviation (SD). RU, response units.