Guanine nucleotide-binding protein G(t) subunit alpha-1

UniProt P04695 Organism Bos taurus Gene GNAT1 EC 3.6.5.-

Also known as: GNAT1

Function

Alpha subunit of the heterotrimeric guanine nucleotide-binding protein (G protein) that transduces signals from the G protein-coupled photoreceptor rhodopsin (RHO). Required for normal RHO-mediated light perception in retinal rod photoreceptors (By similarity). Functions as a GTPase that contains the guanine nucleotide binding site and cycles between an active GTP-bound state and an inactive GDP-bound state. Under dim light conditions, RHO promotes GDP release and GTP binding. Activates downstream effectors, including cone cGMP-phosphodiesterase (PDE6), to mediate the phototransduction cascade. Stimulates PDE6 by binding and repositioning the PDE6 gamma inhibitory subunits (PDE6G) to promote catalytic activity.

Classification

Family (Pfam): PF00503 G-alpha
InterPro: Gprotein_alpha_I, Gprotein_alpha_su, GproteinA_insert, P-loop_NTPase
Functional cluster: Small GTPases (Ras/Rab) & related

Experimental structures · PDB · 18

1AQG NMR
1FQJ X-ray 2.02A
1FQK X-ray 2.30A
1GOT X-ray 2.00A
1LVZ NMR
1TAD X-ray 1.70A
1TAG X-ray 1.80A
1TND X-ray 2.20A
2X72 X-ray 3.00A
3DQB X-ray 3.20A
3PQR X-ray 2.85A
3V00 X-ray 2.90A
… and 6 more

A predicted model is available from AlphaFold.

Gene Ontology · 22

Neighborhood · nearest proteins

Nearest neighbours of Guanine nucleotide-binding protein G(t) subunit alpha-1: 3 by sequence/function similarity (left); 3 co-cited in the literature (right).

Related proteins · sequence + function similarity

Co-cited proteins · studied together in the literature

Rhodopsin 6 shared papers
Rod cGMP 3',5'-cyclic phosphodiesterase subunit gamma 3 shared papers
Rod cGMP-specific 3',5'-cyclic phosphodiesterase subunit beta 2 shared papers
Rod cGMP-specific 3',5'-cyclic phosphodiesterase subunit alpha 2 shared papers
Regulator of G protein signaling 9 1 shared papers

Literature · 21 cited papers

Probing the mechanism by which the retinal G protein transducin activates its biological effector PDE6. J. Biol. Chem. · 2024
Structure of the Visual Signaling Complex between Transducin and Phosphodiesterase 6. Mol. Cell · 2020
Structures of the Rhodopsin-Transducin Complex: Insights into G-Protein Activation. Mol. Cell · 2019
Isolation and structure-function characterization of a signaling-active rhodopsin-G protein complex. J. Biol. Chem. · 2017
Insights into congenital stationary night blindness based on the structure of G90D rhodopsin. EMBO Rep. · 2013
Asymmetry of the rhodopsin dimer in complex with transducin. FASEB J. · 2013
Crystal structure of metarhodopsin II. Nature · 2011
The structural basis of agonist-induced activation in constitutively active rhodopsin. Nature · 2011
A dominant-negative Galpha mutant that traps a stable rhodopsin-Galpha-GTP-betagamma complex. J. Biol. Chem. · 2011
Crystal structure of opsin in its G-protein-interacting conformation. Nature · 2008
New insights into the role of conserved, essential residues in the GTP binding/GTP hydrolytic cycle of large G proteins. J. Biol. Chem. · 2006
Structural determinants for regulation of phosphodiesterase by a G protein at 2.0 A. Nature · 2001
… and 9 more in the literature graph

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