Balkan, Seyda Tuğçe
GPCR’s are seven-transmembrane receptors that transmit external signals to the intracellular environment via secondary messenger systems through heterotrimeric G proteins. Heterotrimeric G proteins consist of α and β-γ subunits. Until recent years, scientists thought that GPCR signal transduction occurs between one GPCR and one heterotrimeric G protein; however, recently, it has been shown that GPCR’s can make oligomers. Oligomerization of GPCR allows cells to tune the intensity of the signal and respond appropriately. Studies with A1 and A2A heterotetramer and A2A – D2R heterotetramer showed that these interactions theoretically allow G protein α subunit dimer formation according to Navarro et al. and Ferré et al. This theoretical interaction has never been validated via an advanced fluorescent microscopy technique like FRET. This technique allows the detection of physical protein-protein interaction of fluorescently labeled proteins via resonance energy transfer between donor and acceptor fluorophores. In this study, Gαi and Gαs interaction was investigated by FRET technique. In addition, the effect of agonist treatment, CGS (CGS-21680), and quinpirole for A2A and D2R heterotetramer, vi respectively, was investigated. Furthermore, based on the G protein family member K-Ras studies, which has high structural homology with G protein α subunits, that forms a homodimer independent from its receptor (Dempke & Heinemann, 2009), we tested the effect of receptor binding on the physical interaction of G protein α subunit using G protein α subunit-specific minigenes.


Investigation of the effect of GPCR oligomerization on the GNAi1 protein homodimerization in live cells using FRET
Nalli, Enise; Son, Çağdaş Devrim; Küçük Baloğlu, Fatma; Department of Biotechnology (2022-1-26)
G-Protein Coupled Receptors (GPCR) are membrane proteins that pass the cell membrane seven times. In classical GPCR signaling pathways, one GPCR-one heterotrimeric G-protein interaction model is enough to transmit the signal to effector proteins. Studies since 2000 showed that one GPCR dimer-one heterotrimeric G-protein interaction model is more likely, and GPCRs having homo- /hetero- dimers interact with a single G⍺-protein. Recently, studies on GPCRs indicated that more than two receptors interact to ...
Detecting g-protein coupled receptor interactions using enhanced green fluorescent protein reassembly
Kumaş, Gözde; Son, Çağdaş Devrim; Yanık, Tülin; Department of Biotechnology (2012)
The largest class of cell surface receptors in mammalian genomes is the superfamily of G protein-coupled receptors (GPCRs) which are activated by a wide range of extracellular responses such as hormones, pheromones, odorants, and neurotransmitters. Drugs which have therapeutic effects on a wide range of diseases are act on GPCRs. In contrast to traditional idea, it is recently getting accepted that G-protein coupled receptors can form homo- and hetero-dimers and this interaction could have important role on...
Interactions between G-protein Coupled Receptors and Ligand Gated Ion Channels (GPCR-LGIC COUPLING)
Son, Çağdaş Devrim(2014-9-30)
Dopamine receptors are members of G-protein coupled receptor superfamily. These receptors are the key point of dopaminergic system, which controls the regulation of memory, attention, food intake, endocrine regulation, psychomotor activity and positive reinforcement. To regulate so many critically important neurological events, dopamine receptors have complex interactions with other receptors and ion channels. In this study, a trimeric complex comprising D2 receptor -which is a subtype of dopamine receptors...
Prediction of protein subcellular localization based on primary sequence data
Özarar, Mert; Atalay, Mehmet Volkan; Department of Computer Engineering (2003)
Subcellular localization is crucial for determining the functions of proteins. A system called prediction of protein subcellular localization (P2SL) that predicts the subcellular localization of proteins in eukaryotic organisms based on the amino acid content of primary sequences using amino acid order is designed. The approach for prediction is to nd the most frequent motifs for each protein in a given class based on clustering via self organizing maps and then to use these most frequent motifs as features...
Investigation of Gai1 protein homodimerization in live cells using förster resonance energy transfer (FRET) and biomolecular fluorescence complementation assay (BIFC)
Atay, Özge; Son, Çağdaş Devrim; Department of Biochemistry (2019)
The classical GPCR signaling pathway, where a heterotrimeric G protein-GPCR interaction is sufficient to transmit the signal to effector proteins has been replaced by a heteromeric G protein-GPCR homo- or hetero-dimer interaction model over the past two decades. These studies demonstrate that GPCRs that interact with each other couple with a heteromeric G protein. In recent years, evidence suggests that dimer of GPCR dimers is required for some complex signal transductions. In these studies, it was proposed...
Citation Formats
S. T. Balkan, “INVESTIGATION OF PHYSICAL INTERACTION BETWEEN Gαi AND Gαs PROTEINS VIA FRET IN LIVE CELLS,” M.S. - Master of Science, Middle East Technical University, 2021.