Transducin

Function

Transducin (TDN) is a heterotrimeric G protein containing 3 chains: α, β and γ which are organized in two subunits: α and βγ. TDN is involved in phototransduction. The absorption of a photon by retinal causes a change in the conformation of rhodopsin into metarhodopsin II. The latter causes activation of TDN. Upon TDN activation the GDP bound to its α subunit is exchanged for the GTP from the cytoplasm. Deactivation of TDN occurs when the GTP bound to the α subunit is hydrolyzed to GDP. Phosducin binds to the βγ subunit of TND preventing its reassociation with the α subunit.

Disease

Relevance

== Structural highlights == .

3D structures of transducin

Updated on 11-June-2014

Transducin-α

1tnd – bTDN + GTPγS - bovine

1tag – bTDN + GDP
3v00 – b/ratTDN + GDP
1tad – bTDN + GDP + AlF4
1fqk – bTDN + RGS9 + GDP + AlF4
1fqj – bTDN + RGS9 + GMP-PDE γ + GDP + AlF4

Transducin-βγ

1tbg – bTDN

2trc, 1a0r, 1b9x, 1b9y – bTDN + phosducin
1omw, 3cik – bTDN + G-protein coupled receptor kinase 2
3v5w – bTDN (mutant) + G-protein coupled receptor kinase 2
3psc, 3pvu, 3pvw, 4mk0 – bTDN + β-adrenergic receptor kinase 1
2bcj – bTDN (mutant) + β-adrenergic receptor kinase 1
3uzs – bTDN + β-adrenergic receptor kinase 1 + RNA
3krw, 3krx – bTDN + G-protein coupled receptor kinase 2 + inhibitor
1xhm – bTDN + peptide
4kfm – hTDN + G-protein activated inward rectifier K+ channel

Transducin-α+βγ

1got – bTDN + GDP

1gg2 – rTDN + GDP - rat
1gp2 – rTDN (mutant) + GDP
3ah8 – bTDN (mutant) + GDP + inhibitor
3sn6 – bTDN (mutant) + endolysine + antibody fragment

References