G-protein Coupled Receptor (GPCR)

G-protein-coupled receptors (GPCRs) are a large family of proteins embedded in cell membranes that act as communication gateways. They detect signals—such as hormones, neurotransmitters, or light—and transmit these messages into the cell to trigger specific responses. When a signal binds to a GPCR, it activates a nearby protein called a G-protein, which then sets off various internal processes. This mechanism helps cells respond appropriately to their environment and is involved in numerous functions, including sensation, immune response, and regulation of mood and metabolism. GPCRs are also important targets for many medications.