Gproteiinikytketyt

Gproteiinikytketyt, known in English as G protein-coupled receptors (GPCRs), constitute a large family of cell surface receptors that play a crucial role in signal transduction. These receptors are involved in a vast array of physiological processes, including vision, olfaction, neurotransmission, and hormonal regulation. They are characterized by their unique structure, which consists of seven transmembrane alpha-helices.

When an extracellular signaling molecule, such as a hormone or neurotransmitter, binds to a GPCR, it induces a conformational change in the receptor. This change, in turn, activates an intracellular G protein. G proteins are heterotrimeric proteins composed of alpha, beta, and gamma subunits. Upon activation, the alpha subunit of the G protein dissociates from the beta-gamma dimer and can then interact with various effector proteins, such as enzymes or ion channels, located within the cell membrane.

The activation of these effector proteins leads to the generation of second messengers, like cyclic AMP (cAMP) or inositol trisphosphate (IP3), which amplify and propagate the signal within the cell, ultimately eliciting a specific cellular response. The diversity of GPCRs and their associated G proteins allows for a wide range of cellular responses to different extracellular stimuli. Due to their central role in cellular communication, GPCRs are important targets for many pharmaceutical drugs.