G protein-coupled receptors (GPCRs) are known to be modulated by membrane cholesterol levels, but whether or not the effects are caused by specific receptor-cholesterol interactions or cholesterol's general effects on the membrane is not well-understood. We performed coarse-grained molecular dynamics (CGMD) simulations coupled with structural bioinformatics approaches on the β₂-adrenergic receptor (β₂AR) and the cholecystokinin (CCK) receptor subfamily. The β₂AR has been shown to be sensitive to membrane cholesterol and cholesterol molecules have been clearly resolved in numerous β₂AR crystal structures. The two CCK receptors are highly homologous and preserve similar cholesterol recognition motifs but despite their homology, CCK₁R shows functional sensitivity to membrane cholesterol while CCK₂R does not. Our results offer new insights into how cholesterol modulates GPCR function by showing cholesterol interactions with β₂AR that agree with previously published data; additionally, we observe differential and specific cholesterol binding in the CCK receptor subfamily while revealing a previously unreported Cholesterol Recognition Amino-acid Consensus (CRAC) sequence that is also conserved across 38% of class A GPCRs. A thermal denaturation assay (LCP-T_m) shows that mutation of a conserved CRAC sequence on TM7 of the β₂AR affects cholesterol stabilization of the receptor in a lipid bilayer. The results of this study provide a better understanding of receptor-cholesterol interactions that can contribute to novel and improved therapeutics for a variety of diseases.

已知 G 蛋白偶联受体 (GPCR) 受膜胆固醇水平调节，但这种影响是由特定受体-胆固醇相互作用引起的还是胆固醇对膜的一般影响引起的尚不清楚。_{我们对 β 2} -肾上腺素能受体 (β ₂ AR) 和胆囊收缩素 (CCK) 受体亚家族进行了粗粒度分子动力学 (CGMD) 模拟以及结构生物信息学方法。β ₂ AR 已被证明对膜胆固醇敏感，并且胆固醇分子已在许多 β ₂ AR 晶体结构中得到清晰的解析。这两种 CCK 受体高度同源，并保留相似的胆固醇识别基序，但尽管它们具有同源性，CCK ₁ R 对膜胆固醇表现出功能敏感性，而 CCK ₂ R 则不然。我们的结果通过显示胆固醇与 β ₂ AR 的相互作用，为胆固醇如何调节 GPCR 功能提供了新的见解，这与之前发表的数据一致；此外，我们观察到 CCK 受体亚家族中差异性和特异性的胆固醇结合，同时揭示了先前未报道的胆固醇识别氨基酸共有 (CRAC) 序列，该序列在 38% 的 A 类 GPCR 中也是保守的。热变性测定（LCP-T _{m ）表明，β 2} AR TM7 上保守的 CRAC 序列的突变会影响脂质双层中受体的胆固醇稳定性。这项研究的结果提供了对受体-胆固醇相互作用的更好理解，有助于为多种疾病提供新颖和改进的治疗方法。