Zhang, Danyang; Lape, Remigijus; Shaikh, Saher A.; Kohegyi, Bianka K.; Watson, JakeISTA ; Cais, Ondrej; Nakagawa, Terunaga; Greger, Ingo H.
AMPA glutamate receptors (AMPARs) mediate excitatory neurotransmission throughout the brain. Their signalling is uniquely diversified by brain region-specific auxiliary subunits, providing an opportunity for the development of selective therapeutics. AMPARs associated with TARP γ8 are enriched in the hippocampus, and are targets of emerging anti-epileptic drugs. To understand their therapeutic activity, we determined cryo-EM structures of the GluA1/2-γ8 receptor associated with three potent, chemically diverse ligands. We find that despite sharing a lipid-exposed and water-accessible binding pocket, drug action is differentially affected by binding-site mutants. Together with patch-clamp recordings and MD simulations we also demonstrate that ligand-triggered reorganisation of the AMPAR-TARP interface contributes to modulation. Unexpectedly, one ligand (JNJ-61432059) acts bifunctionally, negatively affecting GluA1 but exerting positive modulatory action on GluA2-containing AMPARs, in a TARP stoichiometry-dependent manner. These results further illuminate the action of TARPs, demonstrate the sensitive balance between positive and negative modulatory action, and provide a mechanistic platform for development of both positive and negative selective AMPAR modulators.
We thank James Krieger for generating the ‘proDy’ interaction maps in Fig. 5B and S7C, and Jan-Niklas Dohrke for critically reading the manuscript. We thank members of the Greger lab for insightful comments during this study. We acknowledge Trevor Rutherford for confirming ligand integrity by NMR. We are also grateful to LMB scientific computing and the EM facility for their support. This research was funded in part by the Wellcome Trust (223194/Z/21/Z) to I.H.G. For the purpose of Open Access, the MRC Laboratory of Molecular Biology has applied a CC BY public copyright licence to any Author Accepted Manuscript (AAM) version arising from this submission. Further funding came from the Medical Research Council (MRU105174197) to I.H.G, and NIH grant (R56/R01MH123474) to T.N.
Zhang D, Lape R, Shaikh SA, et al. Modulatory mechanisms of TARP γ8-selective AMPA receptor therapeutics. Nature Communications. 2023;14. doi:10.1038/s41467-023-37259-5
Zhang, D., Lape, R., Shaikh, S. A., Kohegyi, B. K., Watson, J., Cais, O., … Greger, I. H. (2023). Modulatory mechanisms of TARP γ8-selective AMPA receptor therapeutics. Nature Communications. Springer Nature. https://doi.org/10.1038/s41467-023-37259-5
Zhang, Danyang, Remigijus Lape, Saher A. Shaikh, Bianka K. Kohegyi, Jake Watson, Ondrej Cais, Terunaga Nakagawa, and Ingo H. Greger. “Modulatory Mechanisms of TARP Γ8-Selective AMPA Receptor Therapeutics.” Nature Communications. Springer Nature, 2023. https://doi.org/10.1038/s41467-023-37259-5.
D. Zhang et al., “Modulatory mechanisms of TARP γ8-selective AMPA receptor therapeutics,” Nature Communications, vol. 14. Springer Nature, 2023.
Zhang D, Lape R, Shaikh SA, Kohegyi BK, Watson J, Cais O, Nakagawa T, Greger IH. 2023. Modulatory mechanisms of TARP γ8-selective AMPA receptor therapeutics. Nature Communications. 14, 1659.
Zhang, Danyang, et al. “Modulatory Mechanisms of TARP Γ8-Selective AMPA Receptor Therapeutics.” Nature Communications, vol. 14, 1659, Springer Nature, 2023, doi:10.1038/s41467-023-37259-5.
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