Selective G protein signaling driven by substance P-neurokinin receptor dynamics.
Harris, J.A., Faust, B., Gondin, A.B., Damgen, M.A., Suomivuori, C.M., Veldhuis, N.A., Cheng, Y., Dror, R.O., Thal, D.M., Manglik, A.(2022) Nat Chem Biol 18: 109-115
- PubMed: 34711980 
- DOI: https://doi.org/10.1038/s41589-021-00890-8
- Primary Citation of Related Structures:  
7RMG, 7RMH, 7RMI - PubMed Abstract: 
The neuropeptide substance P (SP) is important in pain and inflammation. SP activates the neurokinin-1 receptor (NK1R) to signal via G q and G s proteins. Neurokinin A also activates NK1R, but leads to selective G q signaling. How two stimuli yield distinct G protein signaling at the same G protein-coupled receptor remains unclear. We determined cryogenic-electron microscopy structures of active NK1R bound to SP or the G q -biased peptide SP6-11. Peptide interactions deep within NK1R are critical for receptor activation. Conversely, interactions between SP and NK1R extracellular loops are required for potent G s signaling but not G q signaling. Molecular dynamics simulations showed that these superficial contacts restrict SP flexibility. SP6-11, which lacks these interactions, is dynamic while bound to NK1R. Structural dynamics of NK1R agonists therefore depend on interactions with the receptor extracellular loops and regulate G protein signaling selectivity. Similar interactions between other neuropeptides and their cognate receptors may tune intracellular signaling.
Organizational Affiliation: 
Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA.