G protein
These molecules have been described as "biological traffic lights." Located inside the cell, G proteins are able respond to signals outside the cell — light, smell, hormones — and translate (transduce) these signals into action within the cell. Alfred G. Gilman and Martin Rodbell shared the 1994 Nobel Prize in Physiology or Medicine for "their discovery of G- proteins and the role of these proteins in signal transduction in cells."

* * *

G protein 'jē- n any of a class of cell membrane proteins that are coupled to cell surface receptors and upon stimulation of the receptor by an extracellular molecule (as a hormone or neurotransmitter) bind to GTP to form an active complex which mediates an intracellular event (as activation of adenylate cyclase)

* * *

any of a family of similar heterotrimeric proteins of the intracellular portion of the plasma membrane that bind activated receptor complexes and, through conformational changes and cyclic binding and hydrolysis of GTP, directly or indirectly effect alterations in channel gating and so couple cell surface receptors to intracellular responses. Some G proteins are named for their activities, e.g., Gs stimulates and GI inhibits enzyme activity.

Medical dictionary. 2011.

Look at other dictionaries:

  • G protein — [ Phosducin transducin beta gamma complex. Beta and gamma subunits of G protein are shown by blue and red, respectively.] G proteins, short for guanine nucleotide binding proteins, are a family of proteins involved in second messenger cascades. G …   Wikipedia

  • G-Protein — Die Bezeichnung G Protein steht vereinfacht für Guaninnucleotid bindendes Protein oder GTP bindendes Protein. G Proteine besetzen eine Schlüsselposition in der Signalweiterleitung (Signaltransduktion) zwischen Rezeptor und Second Messenger… …   Deutsch Wikipedia

  • G protein — Proteins found on the inner surface of the plasma membrane, which bind to the guanine nucleotides, GTP and GDP. They transmit signals from outside the membrane, via trans membrane (G protein coupled) receptors, to adenylate cyclase, which… …   Glossary of Biotechnology

  • G-protein — G pro·tein (jēʹprō tēn , tē ĭn) n. Any of a class of cell membrane proteins that function as intermediaries between hormone receptors and effector enzymes and enable the cell to regulate its metabolism in response to hormonal changes.   [From GTP …   Universalium

  • G-Protein — G Pro|te|in [Abk. für Guaninnukleotidebindendes Protein]: Sammelbez. für aus 3 Untereinheiten bestehende Proteine, die durch reversible Bindung an die ↑ Guanosinphosphate GTP u. GDP physiol. Signalfortleitungsprozesse in Gang setzen u.… …   Universal-Lexikon

  • g protein — noun Usage: usually capitalized G Etymology: guanosine triphosphate binding protein : any of a class of cell membrane proteins that are coupled to cell surface receptors and upon stimulation of the receptor by an extracellular signalling molecule …   Useful english dictionary

  • G protein — noun Etymology: guanosine triphosphate binding protein Date: 1967 any of a class of cell membrane proteins that are coupled to cell surface receptors and upon stimulation of the receptor by an extracellular signaling molecule (as a hormone or… …   New Collegiate Dictionary

  • G-protein — (1) See GTP binding proteins. (2) The spike glycoprotein of vesicular stomatitis virus. This has been an important protein for investigation of membrane transport in eukaryotic cells …   Dictionary of molecular biology

  • G protein — noun Any of a class of proteins, found in cell membranes, that pass signals between hormone receptors and effector enzymes …   Wiktionary

  • G protein-coupled receptor — G protein coupled receptors (GPCRs), also known as seven transmembrane domain receptors, 7TM receptors, heptahelical receptors, and G protein linked receptors (GPLR), comprise a large protein family of transmembrane receptors that sense molecules …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”