FIGURE 4.

(A) : Model derived from the cryo-EM data of the Torpedo californica electric organ muscle-type nAChR (grey surface rendering) reconstituted in nanodisc with exogenously added soybean lipids. Under these experimental conditions, phospholipid (yellow) and cholesterol (red) molecules are observed on both hemilayers of the receptor transmembrane region (PDB: 7SMQ). Notice the preference of lipids for cavities or crevices between adjacent subunits, and the end-to-end cholesterol doublets on the inner and outer segments of the same transmembrane helices. From ref. (Rahman et al., 2022). Molecular graphics performed with UCSF ChimeraX (Pettersen et al., 2004). (B) : Cholesterol doublets in the γM4 transmembrane domain of the human nAChR, with the calculated free energy of interaction with the CRAC and CARC-like linear cholesterol consensus domains at the exofacial (top)- and cytoplasmic-facing hemilayers, respectively (reviewed in ref (Fantini et al., 2019).). Reproduced from Barrantes, 2023, an open access article distributed under the terms of the Common Access CC BY licence.