Understanding Periperal Membrane Protein Interactions | BPS Thematic Meeting

Understanding Peripheral Membrane Protein Interactions: Structure, Dynamics, Function and Therapy

Poster Abstracts

19-POS Board 19 ALLOSTERIC CONTROL OF GPCR–G-PROTEIN COUPLING REVEALED BY RIGIDITY-BASED MODELING AND 19F-NMR Adnan Sljoka ; 1 RIKEN, Tokyo, Japan G-protein–coupled receptors (GPCRs) transmit signals by recruiting heterotrimeric G proteins where subtle long range perturbations bias coupling and efficacy. We integrate Rigidity Transmission Allostery (RTA) with geometric Monte-Carlo simulations and 19F-NMR to map and validate dynamic and adaptive allosteric pathways that span ligand sites, the transmembrane core and the cytoplasmic G-protein interface reaching across the nucleotide pocket and different subunits of G protein. RTA quantifies how local rigidity perturbations propagate over long distances, predicting allosteric pathway and hotspots that govern G-protein subtype selectivity. A key mechanistic insight is the identification of multiple tryptophan residues positioned along predicted pathways both in receptor and G-protein. We validate these pathways using site specific 5-fluorotryptophan labeling and 19F-NMR, which report on state populations and activation pathways. Using the A2A receptor as an exempla, we show that ionic (e.g., Na+) and lipid interactions reshape allosteric pathways and play a key role in selectivity and efficacy. Our framework unifies computational mechanics with NMR readouts, establishes allostery as a designable feature of GPCR signaling, and suggests testable strategies to modulate GPCR activation and biased signaling. (1.) Sljoka A.*, Structural and Functional Analysis of Proteins Using Rigidity Theory, Sublinear Computation Paradigm, Springer Nature, 2022.(2.) Sljoka A.*, Probing Allosteric Communication with Long-range rigidity transmission across protein networks, In: Di Paola L., Giuliani A. (eds), Allostery. Methods in Molecular Biology, vol 2253. Humana, New York, NY, 2021.(3.) Picard L.P. et al, Kitao A., Sljoka A.*, Prosser S.P., Balancing Promiscuity and Selectivity - Determining Factors Governing G Protein Selectivity and Efficacy for the Adenosine A2A Receptor, Nature Chemical Biology, 41589-024-01682-6, 2024.(4.) Huang S.K., Pandey A., Tran D.T., Villanueva N.L., Kitao A., Sunahara R.K., Sljoka A* and Prosser R.S., Delineating the conformational landscape of the adenosine A 2A receptor during G protein coupling, Cell, 2021.(5.) Huang, S.K., Picard, LP., Rahmatullah, R.S.M. et al. Sljoka, A.* and Prosser S.R. Mapping the conformational landscape of the stimulatory heterotrimeric G protein. Nat Struct Mol Biol (2023).(6.) Ye L., C. Neale, Sljoka A., Pichugin D., Tsuchimura N., Ernst O. P., Sunahara R. and Prosser S., Bidirectional Regulation of the A2A Adenosine G Protein-Coupled Receptor by Physiological Cations, Nature Communication, 1 9:1372, 2018

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