Binding kinetics as a major factor for differential receptor activation profiles

Chemokines are signaling molecules, which drive cell movement by binding to chemokine receptors in cell membranes. There are around fifty different chemokines and twenty chemokine receptors with chemokines typically binding more than one receptor and most receptors binding more than one chemokine. Years of studies have determined the affinities of chemokine for receptors. However, how the selectivity between chemokines is determined remains poorly understood. The kinetics, or how fast the binding happens has gotten far less attention. We hypothesize that characterization of chemokine binding kinetics is crucial to better understand the complexity of the chemokine system and that the rate of binding is an important determinant of chemokine selectivity.