Putative cholesterol recognition/interaction amino acid consensus (CRAC) motifs in human GPCRs. (a) CRAC motifs in transmembrane domains (TMD) of representative GPCRs such as rhodopsin, -adrenergic receptor, and receptor. The position of the starting amino acid residue in the respective CRAC sequence is denoted in parentheses. (b) A schematic representation of the human receptor with its topological and other structural features. The membrane is shown as a bilayer of phospholipids and cholesterol, representative of typical eukaryotic membranes. The putative CRAC motifs are highlighted (in yellow) (adapted from [38]). Coarse-grain molecular dynamics simulations have validated high occupancy of cholesterol at some of the CRAC sites [39]. See text for other details.