Abstract
We have identified the N terminus of the beta subunit as an essential domain for G-protein beta gamma assembly. A C-terminal fragment, beta 1-(130-340), fails to bind gamma unless coexpressed with the complementary N-terminal fragment, beta 1-(1-129). Deletion of the N-terminal 33 residues of beta 1, a region identified by computer algorithm to favor coiled-coil formation, abolishes gamma 2 association. On the basis of these findings, we propose a coiled-coil model of beta gamma interaction and refine this by computer-assisted molecular modeling. The model is tested by further mutagenesis: reversing the charge of residues in beta 1 that are hypothesized to be involved in interhelical salt bridges precludes gamma association. Insertions in the coiled-coil region, which disrupt the proposed hydrophobic interface, prevent gamma association. This structural basis for beta gamma dimerization provides a starting point for the design of beta and gamma mutants that can be used to map regions in beta gamma critical for interactions with the alpha subunit, receptors, and effectors.
Full text
PDF




Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Alber T. Structure of the leucine zipper. Curr Opin Genet Dev. 1992 Apr;2(2):205–210. doi: 10.1016/s0959-437x(05)80275-8. [DOI] [PubMed] [Google Scholar]
- Bubis J., Khorana H. G. Sites of interaction in the complex between beta- and gamma-subunits of transducin. J Biol Chem. 1990 Aug 5;265(22):12995–12999. [PubMed] [Google Scholar]
- Camps M., Carozzi A., Schnabel P., Scheer A., Parker P. J., Gierschik P. Isozyme-selective stimulation of phospholipase C-beta 2 by G protein beta gamma-subunits. Nature. 1992 Dec 17;360(6405):684–686. doi: 10.1038/360684a0. [DOI] [PubMed] [Google Scholar]
- Cohen C., Parry D. A. Alpha-helical coiled coils and bundles: how to design an alpha-helical protein. Proteins. 1990;7(1):1–15. doi: 10.1002/prot.340070102. [DOI] [PubMed] [Google Scholar]
- Conklin B. R., Bourne H. R. Structural elements of G alpha subunits that interact with G beta gamma, receptors, and effectors. Cell. 1993 May 21;73(4):631–641. doi: 10.1016/0092-8674(93)90245-l. [DOI] [PubMed] [Google Scholar]
- Devereux J., Haeberli P., Smithies O. A comprehensive set of sequence analysis programs for the VAX. Nucleic Acids Res. 1984 Jan 11;12(1 Pt 1):387–395. doi: 10.1093/nar/12.1part1.387. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dunn S. D. Effects of the modification of transfer buffer composition and the renaturation of proteins in gels on the recognition of proteins on Western blots by monoclonal antibodies. Anal Biochem. 1986 Aug 15;157(1):144–153. doi: 10.1016/0003-2697(86)90207-1. [DOI] [PubMed] [Google Scholar]
- Fong H. K., Hurley J. B., Hopkins R. S., Miake-Lye R., Johnson M. S., Doolittle R. F., Simon M. I. Repetitive segmental structure of the transducin beta subunit: homology with the CDC4 gene and identification of related mRNAs. Proc Natl Acad Sci U S A. 1986 Apr;83(7):2162–2166. doi: 10.1073/pnas.83.7.2162. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fung B. K., Nash C. R. Characterization of transducin from bovine retinal rod outer segments. II. Evidence for distinct binding sites and conformational changes revealed by limited proteolysis with trypsin. J Biol Chem. 1983 Sep 10;258(17):10503–10510. [PubMed] [Google Scholar]
- Goldsmith P., Gierschik P., Milligan G., Unson C. G., Vinitsky R., Malech H. L., Spiegel A. M. Antibodies directed against synthetic peptides distinguish between GTP-binding proteins in neutrophil and brain. J Biol Chem. 1987 Oct 25;262(30):14683–14688. [PubMed] [Google Scholar]
- Hurley J. B., Fong H. K., Teplow D. B., Dreyer W. J., Simon M. I. Isolation and characterization of a cDNA clone for the gamma subunit of bovine retinal transducin. Proc Natl Acad Sci U S A. 1984 Nov;81(22):6948–6952. doi: 10.1073/pnas.81.22.6948. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ito H., Tung R. T., Sugimoto T., Kobayashi I., Takahashi K., Katada T., Ui M., Kurachi Y. On the mechanism of G protein beta gamma subunit activation of the muscarinic K+ channel in guinea pig atrial cell membrane. Comparison with the ATP-sensitive K+ channel. J Gen Physiol. 1992 Jun;99(6):961–983. doi: 10.1085/jgp.99.6.961. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Iñiguez-Lluhi J. A., Simon M. I., Robishaw J. D., Gilman A. G. G protein beta gamma subunits synthesized in Sf9 cells. Functional characterization and the significance of prenylation of gamma. J Biol Chem. 1992 Nov 15;267(32):23409–23417. [PubMed] [Google Scholar]
- Jelsema C. L., Axelrod J. Stimulation of phospholipase A2 activity in bovine rod outer segments by the beta gamma subunits of transducin and its inhibition by the alpha subunit. Proc Natl Acad Sci U S A. 1987 Jun;84(11):3623–3627. doi: 10.1073/pnas.84.11.3623. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kleuss C., Scherübl H., Hescheler J., Schultz G., Wittig B. Different beta-subunits determine G-protein interaction with transmembrane receptors. Nature. 1992 Jul 30;358(6385):424–426. doi: 10.1038/358424a0. [DOI] [PubMed] [Google Scholar]
- Kleuss C., Scherübl H., Hescheler J., Schultz G., Wittig B. Selectivity in signal transduction determined by gamma subunits of heterotrimeric G proteins. Science. 1993 Feb 5;259(5096):832–834. doi: 10.1126/science.8094261. [DOI] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
- Leberer E., Dignard D., Hougan L., Thomas D. Y., Whiteway M. Dominant-negative mutants of a yeast G-protein beta subunit identify two functional regions involved in pheromone signalling. EMBO J. 1992 Dec;11(13):4805–4813. doi: 10.1002/j.1460-2075.1992.tb05586.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lupas A. N., Lupas J. M., Stock J. B. Do G protein subunits associate via a three-stranded coiled coil? FEBS Lett. 1992 Dec 14;314(2):105–108. doi: 10.1016/0014-5793(92)80952-d. [DOI] [PubMed] [Google Scholar]
- Lupas A., Van Dyke M., Stock J. Predicting coiled coils from protein sequences. Science. 1991 May 24;252(5009):1162–1164. doi: 10.1126/science.252.5009.1162. [DOI] [PubMed] [Google Scholar]
- Mullis K. B., Faloona F. A. Specific synthesis of DNA in vitro via a polymerase-catalyzed chain reaction. Methods Enzymol. 1987;155:335–350. doi: 10.1016/0076-6879(87)55023-6. [DOI] [PubMed] [Google Scholar]
- Muntz K. H., Sternweis P. C., Gilman A. G., Mumby S. M. Influence of gamma subunit prenylation on association of guanine nucleotide-binding regulatory proteins with membranes. Mol Biol Cell. 1992 Jan;3(1):49–61. doi: 10.1091/mbc.3.1.49. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Murakami T., Simonds W. F., Spiegel A. M. Site-specific antibodies directed against G protein beta and gamma subunits: effects on alpha and beta gamma subunit interaction. Biochemistry. 1992 Mar 24;31(11):2905–2911. doi: 10.1021/bi00126a009. [DOI] [PubMed] [Google Scholar]
- O'Shea E. K., Klemm J. D., Kim P. S., Alber T. X-ray structure of the GCN4 leucine zipper, a two-stranded, parallel coiled coil. Science. 1991 Oct 25;254(5031):539–544. doi: 10.1126/science.1948029. [DOI] [PubMed] [Google Scholar]
- O'Shea E. K., Rutkowski R., Kim P. S. Mechanism of specificity in the Fos-Jun oncoprotein heterodimer. Cell. 1992 Feb 21;68(4):699–708. doi: 10.1016/0092-8674(92)90145-3. [DOI] [PubMed] [Google Scholar]
- Pitcher J. A., Inglese J., Higgins J. B., Arriza J. L., Casey P. J., Kim C., Benovic J. L., Kwatra M. M., Caron M. G., Lefkowitz R. J. Role of beta gamma subunits of G proteins in targeting the beta-adrenergic receptor kinase to membrane-bound receptors. Science. 1992 Aug 28;257(5074):1264–1267. doi: 10.1126/science.1325672. [DOI] [PubMed] [Google Scholar]
- Pronin A. N., Gautam N. Interaction between G-protein beta and gamma subunit types is selective. Proc Natl Acad Sci U S A. 1992 Jul 1;89(13):6220–6224. doi: 10.1073/pnas.89.13.6220. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sanger F., Nicklen S., Coulson A. R. DNA sequencing with chain-terminating inhibitors. Proc Natl Acad Sci U S A. 1977 Dec;74(12):5463–5467. doi: 10.1073/pnas.74.12.5463. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schmidt C. J., Neer E. J. In vitro synthesis of G protein beta gamma dimers. J Biol Chem. 1991 Mar 5;266(7):4538–4544. [PubMed] [Google Scholar]
- Schmidt C. J., Thomas T. C., Levine M. A., Neer E. J. Specificity of G protein beta and gamma subunit interactions. J Biol Chem. 1992 Jul 15;267(20):13807–13810. [PubMed] [Google Scholar]
- Simonds W. F., Butrynski J. E., Gautam N., Unson C. G., Spiegel A. M. G-protein beta gamma dimers. Membrane targeting requires subunit coexpression and intact gamma C-A-A-X domain. J Biol Chem. 1991 Mar 25;266(9):5363–5366. [PubMed] [Google Scholar]
- Spiegel A. M., Shenker A., Weinstein L. S. Receptor-effector coupling by G proteins: implications for normal and abnormal signal transduction. Endocr Rev. 1992 Aug;13(3):536–565. doi: 10.1210/edrv-13-3-536. [DOI] [PubMed] [Google Scholar]
- Tang W. J., Gilman A. G. Adenylyl cyclases. Cell. 1992 Sep 18;70(6):869–872. doi: 10.1016/0092-8674(92)90236-6. [DOI] [PubMed] [Google Scholar]
- Whiteway M., Hougan L., Dignard D., Thomas D. Y., Bell L., Saari G. C., Grant F. J., O'Hara P., MacKay V. L. The STE4 and STE18 genes of yeast encode potential beta and gamma subunits of the mating factor receptor-coupled G protein. Cell. 1989 Feb 10;56(3):467–477. doi: 10.1016/0092-8674(89)90249-3. [DOI] [PubMed] [Google Scholar]