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The Protein Pages

Transducin

To see compiled data on further species click on the topics.
To see the reference for the human data click on the data

Editor's Notes from the Literature

Recent update from: 07.07.00

Description
Transducin is a heterotrimer made from a catalytic alpha subunit (GNAT) and an inhibitory beta-gamma-dimer (GNB-GNG) providing the first step of signal amplification in the visual cascade. GNAT is activated on exchange of GDP for GTP on binding to activated rhodopsin. A light activated molecule of rhodopsin can activate up to 1000 molecules of GNAT(1). Activated GNAT binds to one of the inhibiting gamma subunits of cGMP phosphodiesterase (PDEG) to activate the enzyme.

GENE DATA

Subunits: 3
Subunits:

Subunit Rods Cones
alpha GNAT1 GNAT2
beta GNB1 GNB3
gamma GNGT1 GNGT2

Exons:

Subunit Rods Cones
alpha 9 8
beta
10
gamma 3 3

Markers / RFLPs:

Subunit Rods Cones
alpha
D1S424, D1S236
beta

gamma D7S64, D7S1489

Transcripts:

Subunit Rods Cones
alpha 2418 bp 1.7 kb
beta 2.9 kb
gamma
1.1 kb

Regulatory elements:

Subunit Rods Cones
alpha TATAA-Box TATA- und CAAT-box
CCATTAT-box
beta

gamma
CCAAT-box

Primers:

Subunit Rods Cones
alpha
exons 1 - 8
beta
exons 2 - 10
gamma
complete
Chromosomes with Transducin loci

Assignment:

Subunit Rods Cones
alpha 3p22 1p13.3
beta 1pter-p31.2 12pter-p12.3
gamma 7q21.3 17q21

Involvement in Retinal Degenerations:


click here to see a compilation of

CLICK

several Mutations found to underlie

CSNB, Nougaret type

PROTEIN DATA
Amino acids:
Subunit Rods Cones
alpha 350 AA 354 AA
beta
340 AA
gamma 74 AA 69 AA

Mr/ Weight:

Subunit Rods Cones
alpha

beta 36 kDa 37221
gamma

Modifications:

Subunit Rods Cones
alpha

beta

gamma
farnesylated

Cofactors:

Subunit Rods Cones
alpha GTP
RGS9		 GTP
beta

gamma

PROTEIN DATA

Click on entry to see database record online
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Protein Subtype Locus Species EC-No. Swissprot PIR Prosite
Transducin alpha cone GNAT2 Bos taurus EC- P04695 A94279
Transducin alpha rod GNAT1 Bos taurus EC- P04696 A22244 A23155 A23156 JT0013 A61290 A61415
Transducin beta GNB Bos taurus EC- P04901

Transducin beta 1 GNB1 Bos taurus EC-
A24225 A25457
Transducin beta 2 GNB2 Bos taurus EC- P11017 A26617 A28040
Transducin gamma GNG Bos taurus EC- P02698

Transducin alpha 1 rod GNAT1 Canis familiaris EC- Q28300

Transducin beta GNB Canis familiaris EC- P04901

Transducin beta 3 GNB3 Canis familiaris EC- P49147

Transducin gamma GNG Canis familiaris EC- Q08447

Transducin alpha cone GNAT2 Homo sapiens EC- P19087 Q16162 A47219 S18303 JQ0079
Transducin alpha rod GNAT1 Homo sapiens EC- P11488 P19086 S22953 S04699 A36628 A61179 Q30078
Transducin beta 1 GNB1 Homo sapiens EC- P04901 A24853 A24225 PS00678
Transducin beta 2 GNB2 Homo sapiens EC- P11016 B26617 B28040 PS00678
Transducin beta 3 GNB3 Homo sapiens EC- P16520

Transducin gamma 1 GNGT Homo sapiens EC- Q08447 Q16026
PS50058
Transducin gamma rod GNGT1 Homo sapiens EC-
I62760
Transducin alpha 1 rod Gnat-1 Mus musculus EC- P20612 A33352
Transducin alpha 2 cone Gnat-2 Mus musculus EC- P50149

Transducin beta 2 Gnb-2 Mus musculus EC- P54312

Transducin beta 4 Gnb-4 Mus musculus EC- P29387 P63658

Transducin beta 5 Gnb-5 Mus musculus EC- P54314

Transducin beta 1 GNB1 Rattus norvegicus EC- P54311

Transducin beta 2 GNB2 Rattus norvegicus EC- P54313

Transducin beta 3 GNB3 Rattus norvegicus EC- P52287

GENE DATA

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Gene Subtype Locus Species Genbank Unigene Medline
Transducin alpha GNA Bos taurus K03253 K03254 X02440 M11115
85242674 85242675 85213821
Transducin alpha cone GNAT2 Bos taurus M11116
85142187 86315860
Transducin alpha rod GNAT1 Bos taurus M11115
85213821
Transducin beta GNB Bos taurus X03073 M13236
86030675
Transducin beta 1 GNB1 Bos taurus M36430 M13236
86177563
Transducin beta 2 GNB2 Bos taurus M36431 M16480 M16539
99018118
Transducin gamma GNG Bos taurus S62031 S62029 K03255 K02436 K02199
85046503 85063709 85166247 93272877
Transducin gamma 7 GNGT7 Bos taurus M99393
93054770
Transducin alpha 1 rod GNAT1 Canis familiaris Z69597 U65376

Transducin beta GNB Canis familiaris Z75134
96331105
Transducin beta 3 GNB3 Canis familiaris U52916
97409956 97298311
Transducin gamma GNG Canis familiaris Z75156
96331105 97298311
Transducin alpha cone GNAT2 Cricetulus griseus X96664
97148945
Transducin alpha GNAZ Homo sapiens J03260 NM_002073 D90150 Hs.92002 88203641
Transducin alpha cone GNAT2 Homo sapiens S70567 D10377 D10378 D10379 D10380 D10381 D10382 D10383 D10384 Z18859 D90438 D90439 D90440 D90441 D90442 D90443 D90444 D90445 G42982 U66698 Hs.36973 94010942 92038044 94156312
Transducin alpha rod GNAT1 Homo sapiens X63749 X15088 X99440 S38723 AC002077 D90150 NM_000172 Hs.51147 89315237 92310988 88203641
Transducin beta 1 GNB1 Homo sapiens M36430 AF053356 AL031282 AF070603 X04526 Hs.215595
Transducin beta 2 GNB2 Homo sapiens M36429 M16514 M16538 AF053356 NM_005273 Hs.242024
Transducin beta 3 GNB3 Homo sapiens M31328 U47924 Y12050 Y12051 Y12052 Y12053 Y12054 Y12055 Y12056 Y12057 Y12058 Y12059 NM_002075 Hs.71642 90192801 96303695 97228904
Transducin beta5 GNB5 Homo sapiens NM_006578 AF017656 Hs.155090
Transducin gamma 1 GNGT Homo sapiens S62026 S62027 A00020 Z75156 G06733 U41492 AC002076
93272877 96331105
Transducin gamma 3 GNG3 Homo sapiens NM_012202 AF188177 AF092129 Hs.17915
Transducin gamma 7 GNG7 Homo sapiens NM_005145 AC005512 AJ012074 Hs.127828
Transducin gamma cone GNGT2 Homo sapiens AF001158

Transducin gamma rod GNGT1 Homo sapiens S62026 S62027 U41492 U41493
93272877 96299764
Transducin gamma4 GNG4 Homo sapiens NM_004485 U31382 Hs.32976
Transducin gamma5 GNG5 Homo sapiens NM_005274 AH006978 AF038955 U38498 Hs.5322
Transducin alpha 1 rod Gnat-1 Mus musculus J04720 M25506 M25507 M25508 M25509 M25510 M25511 M25512 M25513 L10666 NM_008140 AH002104 U38504 Mm.69061 89214143 94283273
Transducin alpha 2 cone Gnat-2 Mus musculus L10666 NM_008141 Mm.4805
Transducin alpha-z Gnaz Mus musculus L17074
94283273
Transducin beta 2 Gnb-2 Mus musculus U34360 U38505
96141096
Transducin beta 3 rod Gnb-3 Mus musculus M31328 U47930 AC002397 U38494 Mm.12874 96303695 90192801
Transducin beta 4 Gnb-4 Mus musculus S86124 M87286 NM_013531 M63658 Mm.9336 92181467
Transducin beta 5 Gnb-5 Mus musculus L34290 U69145 NM_010313 O64379 AE001105 AE000782 Mm.4702 94350964
Transducin beta1 Gnb1 Mus musculus NM_008142 U29055 X62634 Mm.2344
Transducin gamma Gngt2 Mus musculus AA028742 Mm.46299
Transducin gamma 4 Gng4 Mus musculus AF038593 AF038594 NM_010377 AH006517 U37527 Mm.8006 96067541 98234556
Transducin gamma1 Gng1 Mus musculus U38495

Transducin gamma2 Gng2 Mus musculus NM_010315 AF098488 AF098489 AH007445 U38496 Mm.46767
Transducin gamma3 Gng3 Mus musculus NM_010316 AF069953 U38497 Mm.27307
Transducin gamma5 Gng5 Mus musculus U38498

Transducin gamma7 Gng7 Mus musculus U38499

Transducin alpha Gnaz Rattus norvegicus NM_013189 AH007288 J03773 Rn.10943
Transducin beta 1 GNB1 Rattus norvegicus U34958

Transducin beta 2 GNB2 Rattus norvegicus U34959

Transducin beta 3 GNB3 Rattus norvegicus L29090
95047499
Transducin alpha GNA Xenopus laevis L07771

GENE LOCUS DATA

Click on entry to see database record online
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Gene Subtype Locus Species Genome Database Mouse Genome Database OMIM Locus Link
Transducin alpha GNAZ Homo sapiens

139160 2781
Transducin alpha cone GNAT2 Homo sapiens 120003
139340 2780
Transducin alpha rod GNAT1 Homo sapiens 119277
139330 163500 2779
Transducin beta 1 GNB1 Homo sapiens 119279 Gnb1 189974 2782
Transducin beta 2 GNB2 Homo sapiens 120004
189974 2783
Transducin beta 3 GNB3 Homo sapiens 120005

2784
Transducin beta5 GNB5 Homo sapiens


10681
Transducin gamma 1 GNGT Homo sapiens 118804
189970
Transducin gamma 3 GNG3 Homo sapiens 392655

2785
Transducin gamma 7 GNG7 Homo sapiens 392656

2788
Transducin gamma cone GNGT2 Homo sapiens 118805

2793
Transducin gamma rod GNGT1 Homo sapiens 118804
189970
Transducin gamma4 GNG4 Homo sapiens

604388 2786
Transducin gamma5 GNG5 Homo sapiens

600874 2787
Transducin alpha 1 rod Gnat-1 Mus musculus
Gnat1
14685
Transducin alpha 2 cone Gnat-2 Mus musculus
Gnat2
14686
Transducin alpha-z Gnaz Mus musculus
Gnaz
14687
Transducin beta 2 Gnb-2 Mus musculus
Gnb2
14693
Transducin beta 3 rod Gnb-3 Mus musculus
Gnb3
14695
Transducin beta 4 Gnb-4 Mus musculus


14696
Transducin beta 5 Gnb-5 Mus musculus


14697
Transducin beta1 Gnb1 Mus musculus
Gnb1
14688
Transducin gamma Gngt2 Mus musculus
Gngt2
14710
Transducin gamma 4 Gng4 Mus musculus
Gng4
14706
Transducin gamma1 Gng1 Mus musculus


14699
Transducin gamma2 Gng2 Mus musculus
Gng2
14702
Transducin gamma3 Gng3 Mus musculus
Gng3
14704
Transducin gamma5 Gng5 Mus musculus


14707
Transducin gamma7 Gng7 Mus musculus
Gng7
14708
Transducin alpha Gnaz Rattus norvegicus


25740
Transducin beta 1 GNB1 Rattus norvegicus


24400
Transducin beta 3 GNB3 Rattus norvegicus
Gnb3

References:
1. Chabre,M., Bigay,J., Bruckert,F., Bornancin,F., Deterre,P., Pfister,C., and Vuong,T.M. Visual signal transduction: the cycle of transducin shuttling between rhodopsin and cGMP phosphodiesterase. 1988; Cold Spring Harb.Symp.Quant.Biol. 53 Pt 1: 313-324.
Goto Top Link to PudMed
2. Fagan,K.P., Feinstein,D.S., Scherer,S.W., Tsui,L.C., and Pittler,S.J. Characterization and fine localization of the human transducin gamma subunit gene GNGT1. 1995; Invest.Ophthalmol.Vis.Sci. 36: S773
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3. Fong,S.L. Characterization of the human rod transducin alpha-subunit gene. 1992; Nucleic.Acids.Res. 20: 2865-2870.
Goto Top Link to PudMed
4. Fong,S.L., Hu,H., Maity,S.N., and Fong,W.B. A CCAAT Binding Factor NF-Y Involved In Transcription Of Human Rod Transducin Alpha Subunit (GNAT1) Gene. 1997; Invest.Ophthalmol.Vis.Sci. 38: S241-S241
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5. Fong,S.L., Morris,T.A., and Fong,W.B. Promotor characterization for human cone transducin-a subunit (TCa). 1995; Invest.Ophthalmol.Vis.Sci. 36: S430
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6. Gao,Y.Q., Danciger,M., Akhmedov,N.B., Zhao,D.Y., Heckenlively,J.R., Fishman,G.A., Weleber,R.G., Jacobson,S.G., and Farber,D.B. Exon screening of the genes encoding the beta- and gamma- subunits of cone transducin in patients with inherited retinal disease. 1998; Mol.Vis. 4: 16-16.
Goto Top Link to PudMed
Human Mutation Online
7. Gerber,S., Rozet,J.M., Bonneau,D., Souied,E., Weissenbach,J., Frezal,J., Munnich,A., and Kaplan,J. Exclusion of the cone-specific alpha-subunit of the transducin gene in Stargardt's disease. 1995; Hum.Genet. 95: 382-384.
Goto Top Link to PudMed
8. Levine,M.A., Modi,W.S., and O'Brien,S.J. Chromosomal localization of the genes encoding two forms of the G protein beta polypeptide, beta 1 and beta 3, in man. 1990; Genomics. 8: 380-386.
Goto Top
9. Levine,M.A., Smallwood,P.M., Moen,P.T.J., Helman,L.J., and Ahn,T.G. Molecular cloning of beta 3 subunit, a third form of the G protein beta-subunit polypeptide. 1990; Proc.Natl.Acad.Sci.U.S.A. 87: 2329-2333.
Goto Top Link to PudMed
10. Makino,E.R., Handy,J.W., Li,T., and Arshavsky,V.Y. The GTPase activating factor for transducin in rod photoreceptors is the complex between RGS9 and type 5 G protein beta subunit. 1999; Proc.Natl.Acad.Sci.U.S.A. 96: 1947-1952.
Goto Top Link to PudMed
11. Morris,T.A. and Fong,S.L. Characterization of the gene encoding human cone transducin alpha-subunit (GNAT2). 1993; Genomics. 17: 442-448.
Goto Top Link to PudMed
12. Ngo,J.T., Bateman,J.B., Klisak,I., Mohandas,T., Van Dop,C., and Sparkes,R.S. Regional mapping of a human rod alpha-transducin (GNAT1) gene to chromosome 3p22. 1993; Genomics. 18: 724-725.
Goto Top Link to PudMed
13. Ong,O.C., Hu,K., Rong,H., Lee,R.H., and Fung,B.K. Gene structure and chromosome localization of the G gamma c subunit of human cone G-protein (GNGT2). 1997; Genomics. 44: 101-109.
Goto Top Link to PudMed
14. Scherer,S.W., Feinstein,D.S., Oliveira,L., Tsui,L.C., and Pittler,S.J. Gene structure and chromosome localization to 7q21.3 of the human rod photoreceptor transducin gamma-subunit gene (GNGT1). 1996; Genomics. 35: 241-243.
Goto Top
15. Wilkie,T.M., Chen,Y., Gilbert,D.J., Moore,K.J., Yu,L., Simon,M.I., Copeland,N.G., and Jenkins,N.A. Identification, chromosomal location, and genome organization of mammalian G-protein-coupled receptors. 1993; Genomics. 18: 175-184.
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Dr. rer. medic. Markus Preising, Dipl.Biol.
Molecular Genetics Laboratory
Department of Paediatric Ophthalmology, Strabismology and Ophthalmogenetics
University of Regensburg
Head: Prof. Dr. med. Birgit Lorenz