Transducin

Transducin

Transducin (also called Gt) is a heterotrimeric G protein that is naturally expressed in vertebrate retina rods and cones (a different Transducin gene is expressed in each cell type). Heterotrimeric Transducin (alpha-beta-gamma subunits) is activated by a conformational change in rhodopsin due to the absorption of a photon by rhodopsin's active group retinal; Activation causes the GDP bound to the alpha subunit to be exchanged with GTP from solution and results in activated alpha dissociating from beta-gamma. Active Transducin-alpha then causes cyclic GMP Phosphodiesterase to increase its activity, thereby lowering the concentration of cGMP, an intracellular second-messenger molecule. Decrease in cGMP concentration leads to the closure of cGMP-regulated Na+ and Ca2+ ion channels and a hyperpolarized membrane potential. This chain of signaling events is also called "the vertebrate phototransduction cascade".

The termination of Transducin activity occurs when (active) GTP bound Transducin is hydrolyzed to Transducin-GDP, a process which is accelerated by a complex containing an RGS ("Regulator of G-protein signaling")-protein and the gamma-subunit of the effector, cyclic GMP Phosphodiesterase.

Genes

*,gene|GNAT2,gene|GNAT3

External links

*


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  • Transducin — ist ein so genanntes heterotrimeres G Protein, welches in den Photorezeptorzellen der Netzhaut vorkommt. Es ist ein wesentlicher Bestandteil der visuellen Signaltransduktionskaskade. Als G Protein besteht es aus drei unterschiedlichen… …   Deutsch Wikipedia

  • transducin — A GTP binding protein found in the disc membrane of retinal rods and cones: of the part of the cascade involved in transduction of light to a nervous impulse. A complex of three subunits; a (39 kD), b (36 kD) and g (8 kD). Photoexcited rhodopsin… …   Dictionary of molecular biology

  • transducin — noun Any of a class of proteins associated with the visual process …   Wiktionary

  • transducin — A protein that binds guanine nucleotides ( I.E., a G protein), found in retinal rods and cones, that plays a major role in signal transduction; in vertebrate rod cells it acts as a link of the photolysis of rhodopsin …   Medical dictionary

  • Transducin — Trans|du|cin [lat. transducere, traducere = überbringen, hinüberführen; ↑ in (3)], das; s; Syn.: Transductase: ein am Sehprozess beteiligtes Enzym (ein G Protein, MG 82 000) …   Universal-Lexikon

  • TLE1 — Transducin like enhancer of split 1 (E(sp1) homolog, Drosophila), also known as TLE1, is a human gene.cite web | title = Entrez Gene: TLE1 transducin like enhancer of split 1 (E(sp1) homolog, Drosophila)| url =… …   Wikipedia

  • TLE2 — Transducin like enhancer of split 2 (E(sp1) homolog, Drosophila), also known as TLE2, is a human gene.cite web | title = Entrez Gene: TLE2 transducin like enhancer of split 2 (E(sp1) homolog, Drosophila)| url =… …   Wikipedia

  • TLE1 — Transducin like enhancer of split 1 Estructura tridimensional de la proteína TLE1. HUGO …   Wikipedia Español

  • TBL3 — Transducin (beta) like 3, also known as TBL3, is a human gene.cite web | title = Entrez Gene: TBL3 transducin (beta) like 3| url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene Cmd=ShowDetailView TermToSearch=10607| accessdate = ] PBB Summary… …   Wikipedia

  • TLE3 — Transducin like enhancer of split 3 (E(sp1) homolog, Drosophila), also known as TLE3, is a human gene.cite web | title = Entrez Gene: TLE3 transducin like enhancer of split 3 (E(sp1) homolog, Drosophila)| url =… …   Wikipedia

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