Eaton, Megan M.Germann, Allison L.Arora, RubyCao, Lily Q.Gao, XiaoyiShin, Daniel J.Wu, AlbertChiara, DavidCohen, JonathanSteinbach, Joe HenryEvers, Alex S.Akk, Gustav2017-05-012016Eaton, M. M., A. L. Germann, R. Arora, L. Q. Cao, X. Gao, D. J. Shin, A. Wu, et al. 2016. “Multiple Non-Equivalent Interfaces Mediate Direct Activation of GABAA Receptors by Propofol.” Current Neuropharmacology 14 (7): 772-780. doi:10.2174/1570159X14666160202121319. http://dx.doi.org/10.2174/1570159X14666160202121319.http://nrs.harvard.edu/urn-3:HUL.InstRepos:32630532Abstract: Background Propofol is a sedative agent that at clinical concentrations acts by allosterically activating or potentiating the γ-aminobutyric acid type A (GABAA) receptor. Mutational, modeling, and photolabeling studies with propofol and its analogues have identified potential interaction sites in the transmembrane domain of the receptor. At the “+” of the β subunit, in the β-α interface, meta-azipropofol labels the M286 residue in the third transmembrane domain. Substitution of this residue with tryptophan results in loss of potentiation by propofol. At the “-” side of the β subunit, in the α-β interface (or β-β interface, in the case of homomeric β receptors), ortho-propofol diazirine labels the H267 residue in the second transmembrane domain. Structural modeling indicates that the β(H267) residue lines a cavity that docks propofol with favorable interaction energy. Method We used two-electrode voltage clamp to determine the functional effects of mutations to the “+” and “-” sides of the β subunit on activation of the α1β3 GABAA receptor by propofol. Results: We found that while the individual mutations had a small effect, the combination of the M286W mutation with tryptophan mutations of selected residues at the α-β interface leads to strong reduction in gating efficacy for propofol. Conclusion: We conclude that α1β3 GABAA receptors can be activated by propofol interactions with the β-β, α-β, and β-α interfaces, where distinct, non-equivalent regions control channel gating. Any interface can mediate activation, hence substitutions at all interfaces are required for loss of activation by propofol.en-USActivationbinding siteGABAmutationpropofolstructureJournal Article2017-05-0110.2174/1570159X14666160202121319