6th International Congress of the Molecular Biology Association of turkey, İzmir, Turkey, 5 - 08 September 2018
The classical GPCR signaling pathway where, a heterotrimeric G proteinGPCR interaction is sufficient to transmit the signal to effector proteins, has been replaced by a heteromeric G proteinGPCR homo or heterodimer interaction model over the past two decades. These studies demonstrate that GPCRs that interact with each other or other GPCRs interact with a heteromeric G protein. In recent years, evidence suggest that dimer of GPCR dimers is required for some complex signal transductions.
In these studies, it was proposed that this heteromeric tetramer formed by the dimerization of the dimers brought two G proteins close enough for proteinprotein interaction. It is not clear if GPCR tetramerization is required for Gprotein dimerization or dimerization can occure indipendent of the GPCRs. On the other hand, studies on small Gproteins (Ras family), which are structural homologs of G alpha subunits of heteromeric Gproteins, shown that dimerization can be independent of the receptors and necessary for various signaling pathways. Within the scope of this study, interactions of Gα proteins with each other were qualitatively and quantitatively investigated in live cells using bimolecular fluorescent complementation assay (BiFC) and Förster resonance energy transfer (FRET) methods. Results strongly suggest that GαiGαi interaction occures in N2a cell cultures. Findings of this study will help us understand the molecular mechanisms required for Gα dimerization and the dynamics of these proteins. Also, GPCR interactions with various effectors during complex signal transductions and the requirement of these receptors during Gα dimerizations can be studied with the techniques optimized in this study.