GPCRs, short for G-Protein Coupled Receptors, are a class of cell membrane proteins that play a crucial role in cellular signal transduction. These receptors are widely distributed throughout various organisms, including humans, and are involved in numerous physiological processes in the body.
GPCRs function as molecular switches, receiving signals from external stimuli such as hormones, neurotransmitters, and light, and transmitting them into intracellular responses. They are composed of a single polypeptide chain folded into seven transmembrane helices, with the extracellular and intracellular regions responsible for ligand binding and signaling, respectively.
Upon stimulation by a specific ligand, GPCRs undergo conformational changes, leading to the activation of intracellular G-proteins, which serve as molecular messengers. The G-proteins subsequently initiate a series of downstream signaling cascades, modulating cellular processes such as gene expression, neurotransmission, sensory perception, and immune responses.
Due to their fundamental role in cellular communication, GPCRs have become a major target for drug development. Approximately 30% of currently prescribed drugs target GPCRs, including medications for cardiovascular diseases, mental disorders, and asthma. The study of GPCRs has led to enormous advancements in pharmacology and molecular biology, contributing to the development of novel therapeutic strategies.
In summary, GPCRs are a diverse family of cell membrane proteins that sense external signals and activate intracellular signaling pathways. They are central to various physiological processes within the body and are prominent drug targets for therapeutic interventions.
