Partial cDNA sequence of the gamma subunit of transducin

Dop, Cornelis Van; Medynski, Daniel; Sullivan, Kathleen; Wu, Anna M.; Fung, Bernard K.-K.; Bourne, Henry R.

doi:10.1016/0006-291x(84)90944-6

Cited by 26 publications

(7 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The structure and function of transducin has been studied by the analysis of cDNA clones for the 'y and a subunits (4)(5)(6)(7)(8)(9)(10). The molecular cloning of cDNA for the a subunit of bovine transducin has revealed the presence of two closely related retina-specific proteins that possess significant sequence homology to each other, ras oncogene proteins and elongation factors of protein synthesis.…”

mentioning

confidence: 99%

“…TY and Ras proteins were also noted to have similar COOH-terminal sequences (4). The expression of TY and Ta gene products appears to be retina specific (9,10). On the other hand, the 3 subunits of transducin and of other G proteins from various tissues are structurally highly conserved on the basis of immunological studies, amino acid composition, and proteolytic peptide mapping, suggesting that the 13 gene product may be ubiquitous (11)(12)(13)(14).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Repetitive segmental structure of the transducin beta subunit: homology with the CDC4 gene and identification of related mRNAs.

Fong¹,

Hurley²,

Hopkins³

et al. 1986

Proc. Natl. Acad. Sci. U.S.A.

380

166

View full text Add to dashboard Cite

Retinal transducin, a guanine nucleotide regulatory protein (referred to as a G protein) that activates a cGMP phosphodiesterase in photoreceptor cells, is comprised of three subunits. We have identified and analyzed cDNA clones of the bovine transducin (3 subunit that may be highly conserved or identical to that in other G proteins. From the cDNA nucleotide sequence of the entire coding region, the primary structure of a 340-amino acid protein was deduced. The encoded (3 subunit has a Mr of 37,375 and is comprised of repetitive homologous segments arranged in tandem. Furthermore, significant homology in primary structure and segmental sequence exists between the 13 subunit and the yeast CDC4 gene product. The Mr 37,37518 subunit polypeptide is encoded by a 2.9-kilobase (kb) mRNA. However, there exists in retina other fl-related mRNAs that are divergent from the 2.9-kb mRNA on the basis of oligonucleotide and primer-extended probe hybridizations. All mammalian tissues and clonal cell lines that have been examined contain at least two P-related mRNAs, usually 1.8 and 2.9 kb in length. These results suggest that the mRNAs are the processed products of a small number of closely related genes or of a single highly complex 1B gene.

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

Repetitive segmental structure of the transducin beta subunit: homology with the CDC4 gene and identification of related mRNAs.

Fong¹,

Hurley²,

Hopkins³

et al. 1986

Proc. Natl. Acad. Sci. U.S.A.

380

166

View full text Add to dashboard Cite

show abstract

“…Previously, we (28) and others (29)(30)(31) have reported on the amino acid sequence of the fy subunit of ROS GTPase. We used an immunological approach in which polyclonal antibodies against native bovine ROS GTPase were used for probing a cDNA library constructed in the Xgtll expression vector (32).…”

mentioning

confidence: 95%

GTPase of bovine rod outer segments: the amino acid sequence of the alpha subunit as derived from the cDNA sequence.

Yatsunami¹,

Khorana²

1985

Proc. Natl. Acad. Sci. U.S.A.

151

View full text Add to dashboard Cite

The sequence of the 350 amino acids in the a subunit of GTPase of bovine rod outer segments has been determined. Enriched GTPase mRNA was used to prepare a cDNA library in the expression vector Xgtll and several overlapping cDNA clones corresponding to the a subunit of the GTPase were identified. The cDNA sequence determined contains 93 nucleotides upstream of the 5' end of the coding region, 1050 nucleotides that specify the amino acid sequence, and 45 nucleotides downstream from the 3' end. The previously described partial amino acid sequences and the sequences at the ADP-ribosylation sites for cholera and pertussis toxins are all confirmed and fitted into the present complete sequence. Homologies are found between the sequence of the a subunit and those of other guanine nucleotide-binding proteins, the ras proteins, peptide chain elongation factors EF-Tu and EF-G, and the initiation factor IF2.Early events in light transduction in the vertebrate rod cell involve photoexcitation of rhodopsin (1) (Mr,41,000) is ADP-ribosylated by pertussis toxin (11). Interestingly, the a subunit of ROS GTPase (Mr, 39,000) can be ADP-ribosylated at distinct sites by pertussis toxin in the dark (12) and by cholera toxin in the light (13). The ,B subunits derived from each of the three proteins, ROS GTPase, Gs, and G,, are strikingly similar, as judged from their amino acid compositions and from maps of proteolytic products (9).Finally, in all cases, the small y subunits are found tightly bound to the 8 subunit (14-16).Recently, a family of ras oncogene products that bind GTP has been characterized (17,18 ROS GTPase (21,22) also have homologies with the corresponding regions in the ras proteins (23-27).Previously, we (28) and others (29-31) have reported on the amino acid sequence of the fy subunit of ROS GTPase. We used an immunological approach in which polyclonal antibodies against native bovine ROS GTPase were used for probing a cDNA library constructed in the Xgtll expression vector (32). We have now used the same approach in deriving the cDNA sequence of the a subunit of ROS GTPase and report on the complete amino acid sequence, 350 residues, of this subunit. A comparison of the sequence with those of other guanine nucleotide-binding proteins, and of the ras proteins, indeed reveals marked homologies.

show abstract

“…@ and y exist as a stable complex and participate in the association of G-protein with membranes and its interaction with photoexcited rhodopsin (Shinozawa et al, 1980;Kuhn, 1984). The retinal G-protein shows striking structural and functional resemblance to the regulatory G-proteins from other signal transducing systems [Shinozawa et al, 1979;Manning & Gilman, 1983;Tanabe et al, 1982;Medynski et al, 1982;Hurley et al, 1984a,b;Sugimoto et al, 1985;Van Dop et al, 1984a;Ovchinikov et al, 1985;Sibley & Lefkowitz, 1985;reviewed by Stryer and Bourne (1986) and Gilman (1 987)]. Moreover, bovine rhodopsin shows significant amino acid sequence homology with the mammalian @-adrenergic receptor (Dixon et al, 1986).…”

mentioning

confidence: 99%

Rhodopsin-G-protein interactions monitored by resonance energy transfer

Borochov‐Neori

Montal²

1989

Biochemistry

View full text Add to dashboard Cite

Resonance energy transfer measurements were implemented to monitor the specific interactions between G-protein and rhodopsin in phospholipid vesicles reconstituted with the purified proteins. Fluorescently labeled G-protein was extracted from bleached rod outer segments (ROS) reacted with several sulfhydryl reagents: N-(1-pyrenyl)maleimide (P), monobromobimane (B), 7-(diethylamino)-3-(4-maleimidylphenyl)-4-methylcoumarin (C), and N-(4-anilino-1-naphthyl)maleimide (A). Limited labeling of ROS, resulting in the modification of less than a single -SH residue per G-protein molecule and less than 0.2 residue per rhodopsin, did not impair the specific in situ interactions between rhodopsin and G-protein. This was demonstrated by preservation of their light-activated tight association and Gpp(NH)p binding and their fast dissociation with excess GTP. The distribution of fluorescent label among the three subunits of G-protein revealed a highly reactive -SH group in the gamma subunit accessible to labeling when G-protein was bound specifically to bleached rhodopsin. Recombination of purified fluorescent derivatives of G-protein with purified rhodopsin reconstituted in lipid vesicles restored the light-activated Gpp(NH)p binding to a level comparable to that measured with unlabeled G-protein. Similar observations were obtained with ROS depleted of peripheral proteins. Likewise, modification of up to two -SH groups per rhodopsin molecule with the fluorescent reagents did not affect the functional recombination of G-protein with rhodopsin in reconstituted lipid vesicles or in depleted ROS. Interactions between rhodopsin and G-protein were monitored by resonance energy transfer measurements, with the following fluorescent conjugates as donor/acceptor couples: P-rhodopsin/C-G-protein, P-rhodopsin/B-G-protein, and P-G-protein/C-rhodopsin.(ABSTRACT TRUNCATED AT 250 WORDS)

show abstract

Partial cDNA sequence of the gamma subunit of transducin

Cited by 26 publications

References 13 publications

Repetitive segmental structure of the transducin beta subunit: homology with the CDC4 gene and identification of related mRNAs.

Repetitive segmental structure of the transducin beta subunit: homology with the CDC4 gene and identification of related mRNAs.

GTPase of bovine rod outer segments: the amino acid sequence of the alpha subunit as derived from the cDNA sequence.

Rhodopsin-G-protein interactions monitored by resonance energy transfer

Contact Info

Product

Resources

About