02400nas a2200181   4500008004100000245010500041210006900146260000800215300001100223490000900234520173200243100002501975700002402000700001702024700002602041700002002067856013102087       2017                        eng d00aRole of spatial inhomogenity in GPCR dimerisation predicted by receptor association-diffusion models0 aRole of spatial inhomogenity in GPCR dimerisation predicted by r  cJUN  a0360020 v14  3 aG protein-coupled receptor (GPCR) association is an emerging paradigm with far reaching implications in the regulation of signalling pathways and therapeutic interventions. Recent super resolution microscopy studies have revealed that receptor dimer steady state exhibits sub-second dynamics. In particular the GPCRs, muscarinic acetylcholine receptor M-1 (M1MR) and formyl peptide receptor (FPR), have been demonstrated to exhibit a fast association/dissociation kinetics, independent of ligand binding. In this work, we have developed a spatial kinetic Monte Carlo model to investigate receptor homo-dimerisation at a single receptor resolution. Experimentally measured association/dissociation kinetic parameters and diffusion coefficients were used as inputs to the model. To test the effect of membrane spatial heterogeneity on the simulated steady state, simulations were compared to experimental statistics of dimerisation. In the simplest case the receptors are assumed to be diffusing in a spatially homogeneous environment, while spatial heterogeneity is modelled to result from crowding, membrane micro-domains and cytoskeletal compartmentalisation or 'corrals'. We show that a simple association-diffusion model is sufficient to reproduce M1MR association statistics, but fails to reproduce FPR statistics despite comparable kinetic constants. A parameter sensitivity analysis is required to reproduce the association statistics of FPR. The model reveals the complex interplay between cytoskeletal components and their influence on receptor association kinetics within the features of the membrane landscape. These results constitute an important step towards understanding the factors modulating GPCR organisation.1 aDeshpande, Sneha, A.1 aPawar, Aiswarya, B.1 aDighe, Anish1 aAthale, Chaitanya, A.1 aSengupta, Durba  uhttps://library.ncl.res.in/content/role-spatial-inhomogenity-gpcr-dimerisation-predicted-receptor-association-diffusion-models