Clustering, Crosstalk and Signalling of Cell Receptors

We propose a general theory of cooperativity between transmembrane receptors of a cell. Based on a conformation-dependent interaction between nearest-neighboring receptors, the sensitive signalling and the enhancement of clustering, or oligomerization, are explained as two responses to ligand binding. In this model, ligand binding shifts the energy difference between the two conformational states. In order to decrease the total energy of the system, neighboring receptors tend to have a same conformational state, while receptors with the same conformational state tend to cluster together. In the presence of noise, there is a probability distribution of various configurations of the system. This situation is investigated by using methods of statistical mechanics. By choosing an appropriate value of coupling-noise-ratio, any degree of signalling sensitivity that fits the reality can be obtained. On the other hand, ligand binding enhances the clustering if the threshold value of the receptor conformational change is within a certain range.