GPCRFamilie

GPCRFamilie refers to the superfamily of G protein-coupled receptors (GPCRs), a large and diverse group of cell-surface receptors that translate extracellular signals into intracellular responses. GPCRs detect a wide range of ligands, including photons, ions, biogenic amines, amino acids, peptides, nucleotides, lipids, and larger hormones or pheromones, allowing cells to respond dynamically to their environment.

Structure and mechanism are central to GPCR function. All GPCRs share a characteristic seven-transmembrane helix architecture, with extracellular regions forming the ligand-binding site and intracellular loops and tails engaging intracellular signaling partners. Upon ligand binding, GPCRs induce conformational changes that promote GDP-to-GTP exchange on the Gα subunit of heterotrimeric G proteins (Gαβγ). This leads to dissociation of the Gα-GTP and Gβγ subunits, which in turn regulate downstream effectors such as adenylyl cyclase, phospholipase C, and various ion channels. Signaling can also proceed via β-arrestins, which contribute to receptor desensitization and alternative signaling pathways.

Classification and diversity are notable features. GPCRs are grouped into several families or classes, including rhodopsin-like receptors (class A), secretin-like receptors (class B), metabotropic glutamate receptors (class C), and frizzled/taste receptors (class F); adhesion GPCRs and other related subfamilies are also recognized. The human genome encodes hundreds of GPCR genes, with olfactory receptors representing a large subfamily.

Clinical relevance and research. GPCRs are among the most important targets in pharmacology; a substantial portion of approved drugs act by modulating GPCR signaling. They participate in numerous physiological processes and disease states, making them central to therapeutic development and basic signaling research.