Technical Advance: Surface plasmon resonance-based analysis of CXCL12 binding using immobilized lentiviral particles
B. Vega, L. Martínez Muñoz, B. L. Holgado, P. Lucas, J. M. Rodríguez-Frade, A. Calle, J. L. Rodríguez-Fernández, L. M. Lechuga, J. F. Rodríguez, R. Gutiérrez-Gallego, and M. Mellado
J. Leukoc. Biol. , 90, 2011, 399-408 - DOI: 10.1189/jlb.1010-565
Abstract: Use of SPR-based biosensors is an established method for measuring molecular interactions. Their application to the study of GPCRs is nonetheless limited to detergent-solubilized receptors that can then be reconstituted into a lipid environment. Using the chemokine receptor CXCR4 and its specific ligand CXCL12, we outline here a highly reproducible biosensor method based on receptor presentation on the surface of lentiviral particles; the approach is simple and does not require the use of antibodies to achieve correct receptor orientation on the sensorchip surface. We measured the kinetic parameters of CXCR4/CXCL12 binding in a single step and in real time and evaluated the effect of GAG presentation of chemokines on this interaction. The data indicate that at low concentrations, soluble heparin modulates CXCR4/CXCL12 interaction and at high concentrations, abrogates binding. These observations suggest that in addition to their known role in modulating local chemokine availability, GAG affect the receptor/ligand interaction, although their influence on affinity parameters is very limited. The method will also be useful for quantifying these biomarkers in biological fluids and for the development of high-throughput screening for their antagonists.