GNAT1-GTP binds PDE6 and activates it

Stable Identifier
R-HSA-74065
Type
Reaction [binding]
Species
Homo sapiens
Compartment
photoreceptor disc membrane, cytosol
ReviewStatus
5/5
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GNAT1-GTP binds PDE6 and activates it
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The membrane associated cGMP phosphodiesterase 6 (PDE6) is a tetramer of two catalytic chains, alpha (PDE6A or PDEA) (Pittler et al. 1990) and beta (PDE6B or PDEB) (Weber et al. 1991), and two inhibitory gamma chains (PDE6G or PDEG) (Tuteja et al. 1990). Binding of an activated transducin alpha subunit (GNAT1-GTP) to PDE-gamma relaxes the inhibitory effect of the gamma subunit thereby activating the associated alpha or beta catalytic subunit. Because the binding of GNAT1-GTP to PDE-gamma is one to one, there is no amplification associated with this step. Active Gt alpha (GNAT-GTP) can be inactivated by a slow, intrinsic GTPase activity that hydrolyses GTP to GDP. Once GNAT1 has GDP bound, it no longer binds to the gamma subunit of PDE6 (PDE6-gamma) that then resumes inhibition of the catalytic subunit of PDE6. Some forms of autosomal recessive retinitis pigmentosa and congenital stationary night blindness are caused by mutations in PDE6 (https://sph.uth.edu/retnet/).
Literature References
PubMed ID Title Journal Year
2161380 Isolation and characterization of cDNA encoding the gamma-subunit of cGMP phosphodiesterase in human retina

Mohandas, T, Sparkes, RS, Tuteja, R, Inana, G, Danciger, M, Klisak, I, Tuteja, N, Farber, DB

Gene 1990
2155175 Molecular characterization of human and bovine rod photoreceptor cGMP phosphodiesterase alpha-subunit and chromosomal localization of the human gene

Ledbetter, D, Davis, RL, Champagne, MS, vanTuinen, P, Wasmuth, JJ, McConnell, DG, Baehr, W, Pittler, SJ

Genomics 1990
1720239 Genomic organization and complete sequence of the human gene encoding the beta-subunit of the cGMP phosphodiesterase and its localisation to 4p 16.3

Lin, BY, Riess, O, Weber, B, Hutchinson, G, Kowbel, D, Schappert, K, Andrew, S, Collins, C, Hayden, MR

Nucleic Acids Res. 1991
Participants
Input
Output
Participates
as an event of
This event is regulated
Negatively by
Regulator
GNAT1-GDP [photoreceptor disc membrane] (Homo sapiens)
Inferred From
Gnat1-GTP binds Pde6 and activates it (Bos taurus)
Authored
Schmidt, EE  (2003-07-11)
Reviewed
Makino, C  (2013-04-11)
Created
Carleton, KL  (2003-07-31)
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