Extended Data Fig. 8: Lipid-binding sites and functional modulation of GABAA receptor by PIP2.
From: Cryo-EM structure of the human α1β3γ2 GABAA receptor in a lipid bilayer
a, Well-resolved density for the POPC lipid moiety (yellow, ball-and-stick representation) at the extracellular aspect of the lipid nanodisc. Electron microscopy density is shown in chicken-wire representation and contoured around the lipids. b, Sequence alignment of GABAA receptor and GlyR subunits for PIP2-binding regions: the M1–M2 loop, post-M3 and pre-M4 segments. α1 residues forming hydrogen bonds or salt-bridge interactions with PIP2 are identified by yellow hexagons, and those that are conserved among receptor subunits are highlighted in orange (identical) and yellow (similar). The alignment graphic was prepared on the ESPript 3.0 server (http://espript.ibcp.fr/ESPript/ESPript/). c, Representative normalized current traces from the same patch, obtained in a two-pulse protocol, in which inside-out patches were exposed to two 5-s etomidate (100 μM) pulses, 7.5 s apart. During the second pulse, etomidate was either applied alone or co-applied with poly-l-lysine (250 μg ml−1). Current traces were normalized to the peak-current amplitude obtained during the first etomidate pulse. d, Dot plot of peak-current amplitudes obtained during the second pulse (co-application of poly-l-lysine) normalized to the peak-current amplitudes obtained with the first pulse of etomidate (centre value represents mean ± s.d.; n = 9 patches). Unpaired and paired Student’s t-tests (two-tailed) were used; the P values obtained are indicated on the figure.
