Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

GABAB-receptor subtypes assemble into functional heteromeric complexes

Abstract

B-type receptors for the neurotransmitter GABA (γ-aminobutyric acid) inhibit neuronal activity through G-protein-coupled second-messenger systems, which regulate the release of neurotransmitters and the activity of ion channels and adenylyl cyclase1. Physiological and biochemical studies show that there are differences in drug efficiencies at different GABAB receptors, so it is expected that GABAB-receptor (GABABR) subtypes exist2. Two GABAB-receptor splice variants have been cloned3 (GABABR1a and GABABR1b), but native GABAB receptors and recombinant receptors showed unexplained differences in agonist-binding potencies. Moreover, the activation of presumed effector ion channels in heterologous cells expressing the recombinant receptors proved difficult3,4. Here we describe a new GABAB receptor subtype, GABABR2, which does not bind available GABAB antagonists with measurable potency. GABABR1a, GABABR1b and GABABR2 alone do not activate Kir3-type potassium channels efficiently, but co-expression of these receptors yields a robust coupling to activation of Kir3 channels. We provide evidence for the assembly of heteromeric GABAB receptors in vivo and show that GABABR2 and GABABR1a/b proteins immunoprecipitate and localize together at dendritic spines. The heteromeric receptor complexes exhibit a significant increase in agonist- and partial-agonist-binding potencies as compared with individual receptors and probably represent the predominant native GABAB receptor. Heteromeric assembly among G-protein-coupled receptors has not, to our knowledge, been described before.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Sequence and expression of GABABR2 (R2).
Figure 2: Binding pharmacology of GABABR2 co-expressed with GABABR1a or GABABR1b.
Figure 3: Coupling of GABAB receptors to Kir3 channels in transfected HEK-293 cells and Xenopus oocytes.
Figure 4: Immunoprecipitation analysis of GABAB receptors.
Figure 5: Cellular and subcellular distribution of GABAB-receptor mRNA and protein in rat brain.

Similar content being viewed by others

References

  1. Kerr, D. I. & Ong, J. GABABreceptors. Pharmacol. Ther. 67, 187–246 (1995).

    Article  CAS  Google Scholar 

  2. Bettler, B., Kaupmann, K. & Bowery, N. G. GABABreceptors: drugs meet clones. Curr. Opin. Neurobiol. 8, 345–350 (1998).

    Article  CAS  Google Scholar 

  3. Kaupmann, K.et al. Expression cloning of GABABreceptors uncovers similarity to metabotropic glutamate receptors. Nature 386, 239–246 (1997).

    Article  ADS  CAS  Google Scholar 

  4. Kaupmann, K.et al. Human GABABreceptors are differentially expressed and regulate inwardly rectifying K+_ channels. Proc. Natl Acad. Sci. USA(in the press).

  5. Ward, D. T., Brown, E. M. & Harris, H. W. Disulfide bonds in the extracellular calcium-polyvalent cation-sensing receptor correlate with dimer formation and its response to divalent cations in vitro. J. Biol. Chem. 273, 14476–14483 (1998).

    Article  CAS  Google Scholar 

  6. Romano, C., Yang, W.- & O'Malley, L. Metabotropic glutamate receptor 5 is a disulfide-linked dimer. J. Biol. Chem. 271, 28612–28616 (1996).

    Article  CAS  Google Scholar 

  7. Sodickson, D. L. & Bean, B. P. GABABreceptor-activated inwardly rectifying potassium current in dissociated hippocampal CA3 neurons. J. Neurosci. 16, 6374–6385 (1996).

    Article  CAS  Google Scholar 

  8. Lüscher, C., Jan, L. Y., Stoffel, M., Malenka, R. C. & Nicoll, R. A. Gprotein-coupled inwardly rectifying K+ channels (GIRKs) mediate postsynaptic but not presynaptic transmitter actions in hippocampal neurons. Neuron 19, 687–695 (1997).

    Article  Google Scholar 

  9. Slesinger, P. A., Stoffel, M., Jan, Y. N. & Jan, L. Y. Defective γ-amino butyric acid type B receptor-activated inwardly rectifying K+ currents in cerebellar granule cells isolated from weaver and GIRK2 null mutant mice. Proc. Natl Acad Sci. USA 94, 12210–12217 (1997).

    Article  ADS  CAS  Google Scholar 

  10. Inoue, M., Matsuo, T. & Ogata, N. Characterization of pre- and postsynaptic actions of (−)-baclofen in the guinea-pig hippocampus in vitro. Br. J. Pharmacol. 84, 843–851 (1985).

    Article  CAS  Google Scholar 

  11. Uezono, Y.et al. Activation of inwardly rectifying K+ channels by GABABreceptors expressed in Xenopus oocytes. Neuroreport 9, 583–587 (1998).

    Article  CAS  Google Scholar 

  12. Couve, A.et al. Intracellular retention of recombinant GABABreceptors. J. Biol. Chem. 273, 26361–26367 (1998).

    Article  CAS  Google Scholar 

  13. Hill, D. R., Bowery, N. G. & Hudson, A. L. Inhibition of GABABreceptor binding by guanyl nucleotides. J. Neurochem. 42, 652–657 (1984).

    Article  CAS  Google Scholar 

  14. Morris, S. J., Beatty, D. M. & Chronwall, B. M. GABABR1a/R1b-type receptor antisense deoxynucleotide treatment of melanotropes blocks chronic GABABreceptor inhibition of high-voltage-activated Ca+ channels. J. Neurochem. 71, 1329–1332 (1998).

    Article  CAS  Google Scholar 

  15. Kenakin, T. Differences between natural and recombinant G-protein coupled receptor systems with varying receptor/G-protein stoichiometry. Trends Pharmacol. Sci. 18, 456–464 (1997).

    Article  CAS  Google Scholar 

  16. McLatchie, L. M.et al. RAMPs regulate the transport and ligand specificity of the calcitonin-receptor-like receptor. Nature 393, 333–339 (1998).

    Article  ADS  CAS  Google Scholar 

  17. Dwyer, N. D., Troemel, E. R., Sengupta, P. & Bargmann, C. I. Odorant receptor localization to olfactory cilia is mediated by ODR-4, a novel membrane-associated protein. Cell 93, 455–466 (1998).

    Article  CAS  Google Scholar 

  18. Bischoff, S., Barhanin, J., Bettler, B., Mulle, C. & Heinemann, S. Spatial distribution of kainate receptor subunit mRNA in the mouse basal ganglia and ventral mesencephalon. J. Comp. Neurol. 379, 541–562 (1997).

    Article  CAS  Google Scholar 

  19. Malitschek, B.et al. Developmental changes in agonist affinity at GABABR1 receptor variants in rat brain. Mol. Cell. Neurosci. 12, 56–64 (1998).

    Article  CAS  Google Scholar 

  20. Olpe, H.-R.et al. CGP 35348: a centrally active blocker of GABABreceptors. Eur. J. Pharmacol. 187, 27–38 (1990).

    Article  CAS  Google Scholar 

  21. Shigemoto, R.et al. Target-cell-specific concentration of a metabotropic glutamate receptor in the presynaptic active zone. Nature 381, 523–525 (1996).

    Article  ADS  CAS  Google Scholar 

  22. Wischmeyer, E.et al. Subunit interactions in the assembly of neuronal Kir3.0 inwardly rectifying K+ channels. Mol. Cell. Neurosci. 9, 194–206 (1997).

    Article  CAS  Google Scholar 

  23. Mosbacher, J.et al. P2Y receptor subtypes differentially couple to inwardly rectifying potassium channels. FEBS Lett. 436, 104–110 (1998).

    Article  CAS  Google Scholar 

  24. von Heijne, G. Anew method for predicting signal sequence cleavage sites. Nucleic Acids Res. 14, 4683–4690 (1986).

    Article  CAS  Google Scholar 

  25. O'Hara, P. J.et al. The ligand-binding domain in metabotropic glutamate receptors is related to bacterial periplasmic binding proteins. Neuron 11, 41–52 (1993).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

We thank D. Ristig, A. Begrich, I. Meigel and S. Leonhard for technical assistance.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Bernhard Bettler.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Kaupmann, K., Malitschek, B., Schuler, V. et al. GABAB-receptor subtypes assemble into functional heteromeric complexes. Nature 396, 683–687 (1998). https://doi.org/10.1038/25360

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/25360

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing