A cholesterol analog stabilizes the human ₂-adrenergic receptor nonlinearly with temperature

In cell membranes, G protein-coupled receptors (GPCRs) interact with cholesterol, which modulates their assembly, stability, and conformation. Previous studies have shown how cholesterol modulates the structural properties of GPCRs at ambient temperature. Here, we characterized the mechanical, kinetic, and energetic properties of the human beta(2)-adrenergic receptor (beta(2)AR) in the presence and absence of the cholesterol analog cholesteryl hemisuccinate (CHS) at room temperature (25 degrees C), at physiological temperature (37 degrees C), and at high temperature (42 degrees C). We found that CHS stabilized various structural regions of beta(2)AR differentially, which changed nonlinearly with temperature. Thereby, the strongest effects were observed for structural regions that are important for receptor signaling. Moreover, at 37 degrees C, but not at 25 degrees or 42 degrees C, CHS caused beta(2)AR to increase and stabilize conformational substates to adopt to basal activity. These findings indicate that the nonlinear, temperature-dependent action of CHS in modulating the structural and functional properties of this GPCR is optimized for 37 degrees C.