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dc.contributor.advisorBarlow, Paul
dc.contributor.advisorWyllie, David
dc.contributor.authorPless, Elin
dc.date.accessioned2011-11-25T15:50:38Z
dc.date.available2011-11-25T15:50:38Z
dc.date.issued2010-06-28
dc.identifier.urihttp://hdl.handle.net/1842/5714
dc.description.abstractGABAB receptors are G-protein coupled receptors for the major inhibitory neurotransmitter in the mammalian central nervous system, γ-aminobutyric acid (GABA). The receptor is linked to a variety of disorders including epilepsy, pain, spasticity, drug addiction and cognitive impairment and is, therefore of major importance for drug discovery. The most abundant receptor isoforms GABABR1a and R1b differ by the presence in R1a of a pair of Nterminal extracellular complement control protein modules (CCP1 and CCP2) which - in other proteins - are generally involved in mediating specific protein-protein recognition. The CCP1 module contains disulphides but is natively disordered. In the current work, the yeast two-hybrid system was used to confirm an interaction of CCP1 of GABABR1a with the extracellular protein fibulin-2. Further work with the yeast twohybrid system extablished the novel interaction of the abundant extracellular matrix protein laminin, with GABABR1a CCP1, via its laminin globular (LG) domains. The laminin interaction was further characterised by surface plasmon resonance, demonstrating that several different domains are involved in the binding to the GABAB receptor CCPs. The primary binding site is located on laminin α5 LG4-5, but the E10 domains of the β1 chain and LG1-3 on α1 may also be involved. The pharmacological properties of the GABABR1a and R1b isoforms were studied by transient expression in Xenopus laevis oocytes. It was demonstrated that the agonist baclofen, as well as the antagonist CGP55845, appear to be more potent at GABABR1b compared to GABABR1a. Intriguingly, when recorded in the precence of laminin, GABABR1b/R2 expressing oocytes exhibited an increased baclofen-evoked response while the response in GABABR1a/R2 was completely abolished. In conclusion, the work demonstrates that laminin is a binding partner for GABABR1a CCPs. Such an interaction between the metabotropic GABA receptor and the extracellular matrix may lie behind the recently reported roles of GABA in neuronal migration and the laying down of neuronal circuitry during the development of parts of the central nervous system.en
dc.contributor.sponsorGlaxoSmithKlineen
dc.contributor.sponsorBiotechnology and Biological Sciences Research Council (BBSRC)en
dc.language.isoenen
dc.publisherThe University of Edinburghen
dc.relation.hasversionTiao, J.Y., A. Bradaia, B. Biermann, K. Kaupmann, M. Metz, C. Haller, A.G. Rolink, E. Pless, P.N. Barlow, M. Gassmann, and B. Bettler. 2008. The sushi domains of secreted GABA(B1) isoforms selectively impair GABA(B) heteroreceptor function. J Biol Chem. 283:31005-11.en
dc.subjectGABAB receptorsen
dc.subjectextracellular protein fibulin-2en
dc.subjectlaminin interactionen
dc.subjectsurface plasmon resonanceen
dc.titleInvestigation of interactions with extracellular matrix proteins mediated by the CCP modules of the metabotropic GABAB receptoren
dc.typeThesis or Dissertationen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD Doctor of Philosophyen


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