scholarly journals Label-Free Investigations on the G Protein Dependent Signaling Pathways of Histamine Receptors

2021 ◽  
Vol 22 (18) ◽  
pp. 9739 ◽  
Author(s):  
Ulla Seibel-Ehlert ◽  
Nicole Plank ◽  
Asuka Inoue ◽  
Guenther Bernhardt ◽  
Andrea Strasser
Keyword(s):  
Signal Transduction ◽  
G Protein ◽  
Drug Targets ◽  
Physiological Role ◽  
Histamine Receptors ◽  
Label Free ◽  
Knock Out ◽  
Protein Activation ◽  
Hek Cells ◽  
Molecular Events

G protein activation represents an early key event in the complex GPCR signal transduction process and is usually studied by label-dependent methods targeting specific molecular events. However, the constrained environment of such “invasive” techniques could interfere with biological processes. Although histamine receptors (HRs) represent (evolving) drug targets, their signal transduction is not fully understood. To address this issue, we established a non-invasive dynamic mass redistribution (DMR) assay for the human H1–4Rs expressed in HEK cells, showing excellent signal-to-background ratios above 100 for histamine (HIS) and higher than 24 for inverse agonists with pEC50 values consistent with literature. Taking advantage of the integrative nature of the DMR assay, the involvement of endogenous Gαq/11, Gαs, Gα12/13 and Gβγ proteins was explored, pursuing a two-pronged approach, namely that of classical pharmacology (G protein modulators) and that of molecular biology (Gα knock-out HEK cells). We showed that signal transduction of hH1–4Rs occurred mainly, but not exclusively, via their canonical Gα proteins. For example, in addition to Gαi/o, the Gαq/11 protein was proven to contribute to the DMR response of hH3,4Rs. Moreover, the Gα12/13 was identified to be involved in the hH2R mediated signaling pathway. These results are considered as a basis for future investigations on the (patho)physiological role and the pharmacological potential of H1–4Rs.

G-Protein-Coupled Receptors in Drug Discovery: Nanosizing Using Cell-Free Technologies and Molecular Biology Approaches

2005 ◽  
Vol 10 (8) ◽  
pp. 765-779 ◽  
Author(s):  
Wayne R. Leifert ◽  
Amanda L. Aloia ◽  
Olgatina Bucco ◽  
Richard V. Glatz ◽  
Edward J. McMurchie
Keyword(s):  
Signal Transduction ◽  
G Protein ◽  
Drug Targets ◽  
G Protein Coupled Receptors ◽  
Orphan Receptors ◽  
Molecular Switching ◽  
Physiological Processes ◽  
Current Cell ◽  
G Protein Coupled ◽  
Signaling Components

Signal transduction by G-protein-coupled receptors (GPCRs) underpins a multitude of physiological processes. Ligand recognition by the receptor leads to activation of a genericmolecular switch involving heterotrimeric G-proteins and guanine nucleotides. Signal transduction has been studied extensively with both cell-based systems and assays comprising isolated signaling components. Interest and commercial investment in GPCRs in areas such as drug targets, orphan receptors, highthroughput screening, biosensors, and so on will focus greater attention on assay development to allow for miniaturization, ultra-high throughput and, eventually, microarray/biochip assay formats. Although cell-based assays are adequate for many GPCRs, it is likely that these formatswill limit the development of higher density GPCRassay platforms mandatory for other applications. Stable, robust, cell-free signaling assemblies comprising receptor and appropriate molecular switching components will form the basis of future GPCR assay platforms adaptable for such applications as microarrays. The authors review current cell-free GPCR assay technologies and molecular biological approaches for construction of novel, functional GPCR assays.

Acupuncture Upregulates G Protein Coupled Activity in Samp8 Mice

2017 ◽  
Vol 35 (4) ◽  
pp. 289-296 ◽  
Author(s):  
Benhua Luo ◽  
Lan Zhao ◽  
Xuezhu Zhang ◽  
Bohong Kan ◽  
Yunhe Liu ◽  
...  
Keyword(s):  
Signal Transduction ◽  
G Protein ◽  
Cognitive Deficits ◽  
Control Group ◽  
Protein Activity ◽  
Western Blots ◽  
Protein Activation ◽  
Activation Rate ◽  
Cellular Signal ◽  
Samp8 Mice

Background Transmembrane and intracellular signal transduction of G protein is closely related to the pathophysiology of Alzheimer's disease (AD). Objective To explore the effects of Sanjiao acupuncture on G protein signal transduction pathways in the pathogenesis of AD. Methods 36 senescence-accelerated (SAM) prone 8 mice were divided into three groups that remained untreated (SAMP8, n=12) or received Sanjiao acupuncture (SAMP8+SA, n=12) or control acupuncture (SAMP8+CA, n=12). An additional control group of SAM resistant 1 mice was included (SAMR1 group, n=12). Morris water maze tests were used to investigate learning and memory abilities. Immunoprecipitation and Western blotting were used to study expression of G protein subunits and their activities in the cortex/hippocampus. Results Behavioural analysis showed that acupuncture attenuated the severe cognitive deficits observed in untreated/CA-treated SAMP8 mice. The findings of the G protein activation assays via immunoprecipitation and Western blots were that the physiologically coupled activation rate (PCAR) and maximal coupled activation rate (MCAR) of Gαs and Gαi were decreased in the cortex of SAMP8 vs SAMR1 mice. Sanjiao acupuncture induced an upregulation in the PCAR of Gαs and Gαi. In the hippocampus of untreated SAMP8 mice, the PCAR of Gαs and MCAR of both Gαs and Gαi declined, and Sanjiao acupuncture was associated with an upregulation in the MCAR of Gαs and Gαi. There were no significant differences in Gαs and Gαi expression between the groups. Conclusions Sanjiao acupuncture attenuates cognitive deficits in a mouse model of AD via upregulation of G protein activity and stabilisation of the cellular signal.

Structural and functional aspects of G protein-coupled receptor oligomerization

1998 ◽  
Vol 76 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Terence E Hébert ◽  
Michel Bouvier
Keyword(s):  
Signal Transduction ◽  
G Protein ◽  
Receptor Activation ◽  
Drug Binding ◽  
Receptor Protein ◽  
Surface Receptors ◽  
Receptor Oligomerization ◽  
Gpcr Activation ◽  
Molecular Events ◽  
G Protein Coupled

G protein-coupled receptors (GPCRs) represent the single largest family of cell surface receptors involved in signal transduction. It is estimated that several hundred distinct members of this receptor family in humans direct responses to a wide variety of chemical transmitters, including biogenic amines, amino acids, peptides, lipids, nucleosides, and large polypeptides. These transmembrane receptors are key controllers of such diverse physiological processes as neurotransmission, cellular metabolism, secretion, cellular differentiation, and growth as well as inflammatory and immune responses. GPCRs therefore represent major targets for the development of new drug candidates with potential application in all clinical fields. Many currently used therapeutics act by either activating (agonists) or blocking (antagonists) GPCRs. Studies over the past two decades have provided a wealth of information on the biochemical events underlying cellular signalling by GPCRs. However, our understanding of the molecular interactions between ligands and the receptor protein and, particularly, of the structural correlates of receptor activation or inhibition by agonists and inverse agonists, respectively, is still rudimentary. Most of the work in this area has focused on mapping regions of the receptor responsible for drug binding affinity. Although binding of ligand molecules to specific receptors represents the first event in the action of drugs, the efficacy with which this binding is translated into a physiological response remains the only determinant of therapeutic utility. In the last few years, increasing evidence suggested that receptor oligomerization and in particular dimerization may play an important role in the molecular events leading to GPCR activation. In this paper, we review the biochemical and functional evidence supporting this notion.Key words: G proteins, receptors, dimerization, signal transduction, adrenergic.

scholarly journals Insights from Molecular Dynamics Simulations for GPCR Drug Discovery

2019 ◽  
Author(s):  
Ye Zou ◽  
John Ewalt ◽  
Ho-Leung Ng
Keyword(s):  
Molecular Dynamics ◽  
Drug Discovery ◽  
G Protein ◽  
Drug Targets ◽  
Conformational Dynamics ◽  
Md Simulations ◽  
Protein Activation ◽  
Downstream Signaling ◽  
Dynamics Simulations ◽  
G Protein Coupled

G protein-coupled receptors (GPCRs) are critical drug targets. GPCRs convey signals from the extracellular to the intracellular environment through G proteins. There is evidence that some ligands that bind to the GPCRs activate different downstream signaling pathways. G protein activation or -arrestin biased signaling involves ligands binding to receptors and stabilizing conformations that trigger a specific pathway. Molecular dynamics (MD) simulations are especially valuable for obtaining detailed mechanistic information, including identification of allosteric sites and understanding modulators' interactions between receptors and ligands. Here, we highlight recent simulation studies and methods used to study biased G protein-coupled receptor signaling and their conformational dynamics. We also highlight applications of MD simulations to drug discovery.

Synthetic GPCRs and signal transduction cascades

2019 ◽  
Vol 3 (5) ◽  
pp. 609-614 ◽  
Author(s):  
Colleen Mulvihill ◽  
Andrew Ellington
Keyword(s):  
Signal Transduction ◽  
Synthetic Biology ◽  
Membrane Proteins ◽  
G Protein ◽  
Drug Targets ◽  
G Protein Coupled Receptors ◽  
Complex Signal ◽  
Diverse Group ◽  
Orthogonal Components ◽  
G Protein Coupled

G protein-coupled receptors (GPCRs) are a large and diverse group of membrane proteins that constitute over 30% of FDA approved drug targets. Despite their importance, much remains unknown about GPCR signaling at a system's level. Efforts to engineer receptors with orthogonal components have attempted to provide tools to parse signaling and resultant phenotypes. Recent advances in synthetic biology provide opportunities to engineer receptors at scale and with additional properties that could further inform GPCR biology at a system's level, and enhance the ability to engineer complex signal transduction.

scholarly journals Lipoprotein Proteomics and Aortic Valve Transcriptomics Identify Biological Pathways Linking Lipoprotein(a) Levels to Aortic Stenosis

Metabolites ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 459
Author(s):  
Raphaëlle Bourgeois ◽  
Jérôme Bourgault ◽  
Audrey-Anne Despres ◽  
Nicolas Perrot ◽  
Jakie Guertin ◽  
...  
Keyword(s):  
Risk Factors ◽  
Aortic Valve ◽  
Biological Pathways ◽  
Label Free ◽  
Aortic Valves ◽  
Lipoprotein A ◽  
Protein Activation ◽  
Molecular Events ◽  
Transcriptomic Signature ◽  
Activation Cascade

Lipoprotein(a) (Lp(a)) is one of the most important risk factors for the development of calcific aortic valve stenosis (CAVS). However, the mechanisms through which Lp(a) causes CAVS are currently unknown. Our objectives were to characterize the Lp(a) proteome and to identify proteins that may be differentially associated with Lp(a) in patients with versus without CAVS. Our second objective was to identify genes that may be differentially regulated by exposure to high versus low Lp(a) levels in explanted aortic valves from patients with CAVS. We isolated Lp(a) from the blood of 21 patients with CAVS and 22 volunteers and performed untargeted label-free analysis of the Lp(a) proteome. We also investigated the transcriptomic signature of calcified aortic valves from patients who underwent aortic valve replacement with high versus low Lp(a) levels (n = 118). Proteins involved in the protein activation cascade, platelet degranulation, leukocyte migration, and response to wounding may be associated with Lp(a) depending on CAVS status. The transcriptomic analysis identified genes involved in cardiac aging, chondrocyte development, and inflammation as potentially influenced by Lp(a). Our multi-omic analyses identified biological pathways through which Lp(a) may cause CAVS, as well as key molecular events that could be triggered by Lp(a) in CAVS development.

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