Clustering and Signalling of Cooperative Receptors: a Unified Model

We present a model of cooperativity between transmembrane receptors. Two responses to ligand binding, receptor signalling and the enhancement of clustering, or oligomerization, are unified in the same framework. The model is based on a conformation-dependent interaction between neighboring receptors. 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 treated using analytical and numerical methods of statistical mechanics. Signalling sensitivity is enhanced by an appropriate choice of coupling-noise-ratio. There is a range of the threshold value of receptor conformational change for which clustering is enhanced by ligand binding.