Determining membrane protein quaternary structure is extremely challenging, especially in live cell membranes. We measured the oligomerization of opsin, a prototypical G protein-coupled receptor with pulsed-interleaved excitation fluorescence cross-correlation spectroscopy (PIE-FCCS). Individual cell measurements revealed that opsin is predominantly organized into dimeric clusters. At low concentrations, we observed that the population of oligomers increased linearly with the square of the individual monomer populations. This finding supports a monomer-dimer equilibrium and provides an experimental measurement of the equilibrium constant.
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http://dx.doi.org/10.1021/ja501948w | DOI Listing |
Nat Chem
January 2025
Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, UK.
Understanding the dynamics of membrane protein-ligand interactions within a native lipid bilayer is a major goal for drug discovery. Typically, cell-based assays are used, however, they are often blind to the effects of protein modifications. In this study, using the archetypal G protein-coupled receptor rhodopsin, we found that the receptor and its effectors can be released directly from retina rod disc membranes using infrared irradiation in a mass spectrometer.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Clinical and Chemical Pathology, Ain shams University, Cairo, Egypt.
The expression of CD38 by cancer cells may mediate an immune-suppressive effect by producing Extracellular Adenosine (ADO) acting through G-protein-coupled cell surface receptors on cellular components and tumor cells. This can increase PD-1 expression and interaction with PD-L1, suppressing CD8 + cytotoxic T cells. This study examines the impact of heightened CD38 expression and extracellular ADO on various hematological and clinical parameters in patients with mature B-cell lymphoma, alongside their correlation with the soluble counterparts of the PD-1/PD-L1 axis.
View Article and Find Full Text PDFNPJ Syst Biol Appl
January 2025
BIH Center for Regenerative Therapies (BCRT), Julius Wolff Institute (JWI), and Berlin Institute of Health (BIH); all Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health (BIH), 10117, Berlin, Germany.
Coronavirus disease 2019 (COVID-19) presents a wide spectrum of symptoms, the causes of which remain poorly understood. This study explored the associations between autoantibodies (AABs), particularly those targeting G protein-coupled receptors (GPCRs) and renin‒angiotensin system (RAS) molecules, and the clinical manifestations of COVID-19. Using a cross-sectional analysis of 244 individuals, we applied multivariate analysis of variance, principal component analysis, and multinomial regression to examine the relationships between AAB levels and key symptoms.
View Article and Find Full Text PDFNat Commun
January 2025
IGF, Université de Montpellier, CNRS, INSERM, 34094, Montpellier, France.
The metabotropic glutamate receptors (mGlus) are class C G protein-coupled receptors (GPCR) that form obligate dimers activated by the major excitatory neurotransmitter L-glutamate. The architecture of mGlu receptor comprises an extracellular Venus-Fly Trap domain (VFT) connected to the transmembrane domain (7TM) through a Cysteine-Rich Domain (CRD). The binding of L-glutamate in the VFTs and subsequent conformational change results in the signal being transmitted to the 7TM inducing G protein binding and activation.
View Article and Find Full Text PDFZhongguo Zhong Yao Za Zhi
December 2024
Anhui University of Chinese Medicine Hefei 230012, China Anhui Province Key Laboratory of Application and Transformation of Traditional Chinese Medicine in Prevention and Treatment of Major Pulmonary Diseases Hefei 230031, China Key Laboratory of Xin'an Medicine, Ministry of Education Hefei 230038, China.
This study aimed to investigate the mechanism by which Shegan Mahuang Decoction(SGMH) and its bitter Chinese herbs(BCHs) regulated the lung-gut axis through the bitter taste receptor 14(TAS2R14)/secretory immunoglobulin A(SIgA)/thymic stromal lymphopoietin(TSLP) to intervene in the epithelial cell barrier of cold asthma rats. Fifty SD rats were randomly divided into the following five groups: normal group, model group, dexamethasone group, SGMH group, and BCHs group. A 10% ovalbumin(OVA) solution was used to sensitize the rats via subcutaneous injection on both sides of the abdomen and groin, combined with 2% OVA atomization and cold(2-4 ℃) stimulation to induce a cold asthma model in rats.
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