TY - JOUR T1 - Identifying Functional Hotspot Residues for Biased Ligand Design in G-protein-coupled Receptors JF - Molecular Pharmacology JO - Mol Pharmacol DO - 10.1124/mol.117.110395 SP - mol.117.110395 AU - Anita Nivedha AU - Christofer Tautermann AU - Supriyo Bhattacharya AU - Sangbae Lee AU - Paola Casarosa AU - Ines Kollak AU - Tobias Kiechle AU - Nagarajan Vaidehi Y1 - 2018/01/01 UR - http://molpharm.aspetjournals.org/content/early/2018/01/24/mol.117.110395.abstract N2 - G-protein-coupled receptors (GPCRs) mediate multiple signaling pathways in the cell depending on the agonist that activates the receptor and multiple cellular factors. Agonists that show higher potency to specific signaling pathways over others are known as "biased agonists" and have been shown to have better therapeutic index. Although biased agonists are desirable, their design poses several challenges to date. The number of assays to identify biased agonists seems expensive and tedious. Therefore, computational methods that can reliably calculate the possible bias of various ligands ahead of experiments and provide guidance will be both cost and time effective. In this work, using the mechanism of allosteric communication from the extracellular region to the intracellular transducer protein coupling region in GPCRs, we have developed a computational method, to calculate ligand bias ahead of experiments. We have validated the method for several β-arrestin biased agonists in β2-adrenergic receptor, serotonin receptors 5HT1B and 5HT2B and for G-protein biased agonists in the κ-opioid receptor. Using this computational method, we also performed a blind prediction followed by experimental testing and showed that the agonist carmoterol is β-arrestin biased in β2-adrenergic receptor. Additionally, we have identified amino acid residues in the biased agonist binding site in both β2-adrenergic and κ-opioid receptors that are involved in potentiating the ligand bias. We call these residues as "functional hotspots" and they can be used to derive pharmacophores to design biased agonists in GPCRs. ER -