Gproteingekoppelter

G-protein-coupled receptors (GPCRs) are a large family of membrane-spanning proteins that play a crucial role in cell signaling. They are named for their ability to bind to guanine nucleotides and activate G-proteins, which in turn regulate various intracellular signaling pathways. GPCRs are involved in a wide range of physiological processes, including sensory perception, hormone action, and neurotransmission.

GPCRs are typically composed of seven transmembrane domains, with the extracellular N-terminus and intracellular C-terminus connected by a loop structure. Upon ligand binding, GPCRs undergo a conformational change that activates the associated G-protein. This activation leads to the dissociation of the G-protein into its alpha and beta-gamma subunits, which then regulate downstream effectors such as adenylyl cyclase, phospholipase C, and ion channels.

The G-protein-coupled receptor superfamily is one of the largest in the human genome, with over 800 members identified. They are classified into several subfamilies based on sequence similarity and functional characteristics. Some well-known GPCRs include the rhodopsin family, which is involved in vision, and the opioid receptors, which are targets for pain management.

GPCRs are also important targets for drug development, as they are involved in many diseases, including cardiovascular diseases, neurological disorders, and cancer. The discovery of GPCRs and their signaling mechanisms has opened up new avenues for therapeutic intervention, leading to the development of numerous drugs that modulate GPCR activity.