Gfehérjekapcsolt

Gfehérjekapcsolt is a term used in Hungarian to denote proteins that are associated with G proteins in cellular signaling, most commonly referring to G protein-coupled receptors (GPCRs). The term is not standard in scientific nomenclature, but it is sometimes used as a shorthand to describe receptors that, upon ligand binding, activate heterotrimeric G proteins and propagate signals inside the cell.

In mechanism, a bound ligand induces a conformational change in the receptor, promoting the exchange of GDP for GTP on the Gα subunit of the G protein. This causes the Gα-GTP and Gβγ subunits to dissociate and regulate downstream effectors such as adenylyl cyclase, phospholipase Cβ, and various ion channels. These interactions generate second messengers like cAMP, IP3, and DAG, leading to diverse cellular responses that can affect metabolism, gene expression, ion flux, and cytoskeletal organization.

Structural features of Gfehérjekapcsolt proteins typically include seven transmembrane helices, an extracellular N-terminus, and an intracellular C-terminus, with signaling specificity provided by intracellular loops. They constitute a large and diverse protein family, encompassing classes such as A, B, C, and F GPCRs, and include receptors for photons, odors, neurotransmitters, hormones, and peptides.

Clinical and pharmacological relevance arises from the prevalence of Gfehérjekapcsolt receptors as drug targets. They play critical roles in cardiovascular, nervous system, metabolic, and inflammatory diseases, and many therapeutics act as agonists, antagonists, or allosteric modulators of these receptors.

Research approaches include radioligand binding, heterologous expression systems, functional assays measuring cAMP or Ca2+ signals, and structural methods like cryo-EM and X-ray crystallography. See also GPCR, G protein, and signal transduction.