G-protein-coupled receptors (GPCRs) are a large family of cell surface receptors that play a critical role in signal transduction in cells. They are involved in a wide range of physiological processes, such as vision, smell, taste, and neurotransmission. When a ligand binds to a GPCR on the cell surface, it triggers a conformational change in the receptor, which activates a G protein inside the cell. The G protein then initiates a cascade of intracellular signaling events that ultimately lead to a cellular response. GPCRs are important drug targets and are the target of approximately 30-40% of all prescribed medications. Understanding the structure and function of GPCRs is crucial for the development of new therapeutics for a variety of diseases, including cancer, cardiovascular disease, and neurological disorders. Research in this area focuses on elucidating the structure and function of GPCRs, understanding the signaling pathways they regulate, and developing novel drugs that target these receptors. This research has the potential to lead to the development of more effective and targeted therapies for a wide range of diseases.