a) Microsomes from HEK293 cells expressing PIN1-RFP were separated under native conditions in the presence of NPA or an anti-PIN1 Fab fragment. 1) PIN1-RFP, 2) PIN1-RFP+Fab, 3) PIN1-RFP+10 µM NPA, 4) PIN1-RFP+Fab+10 µM NPA, 5) PIN1-RFP + 10 µM Quercetin (Q), 6) PIN1-RFP+Fab+10 µM Quercetin (Q). Protein complexes were solubilized and separated under native conditions as described before. Western blots were performed with an anti-RFP monoclonal antibody. 