A5002533704- Receptor Mechanisms and Signaling
- Neuroscience and Neuropharmacology Research
- Neuropeptides and Animal Physiology
- Protein Kinase Regulation and GTPase Signaling
- Pancreatic function and diabetes
- Cellular transport and secretion
- Ion channel regulation and function
- Neurotransmitter Receptor Influence on Behavior
- Computational Drug Discovery Methods
- EFL/ESL Teaching and Learning
- Neurobiology and Insect Physiology Research
- Photoreceptor and optogenetics research
- Monoclonal and Polyclonal Antibodies Research
- Second Language Learning and Teaching
- Hearing, Cochlea, Tinnitus, Genetics
- Cell Adhesion Molecules Research
- Genetics and Neurodevelopmental Disorders
- Phosphodiesterase function and regulation
- Chronic Lymphocytic Leukemia Research
- Nicotinic Acetylcholine Receptors Study
- Calpain Protease Function and Regulation
- Ergonomics and Musculoskeletal Disorders
- Infrared Thermography in Medicine
- Glaucoma and retinal disorders
- Adenosine and Purinergic Signaling
McGill University
2014-2025
McGill University Health Centre
2015-2024
Georgia State University
2024
National Institutes of Health
2004-2021
National Institute of Neurological Disorders and Stroke
2007-2021
National Institute on Drug Abuse
2021
Chimerix (United States)
2021
University of Nottingham
2021
Inha University
2007
Pohang University of Science and Technology
1998-2004
Abstract Despite the discovery of heterotrimeric αβγ G proteins ∼25 years ago, their selective perturbation by cell-permeable inhibitors remains a fundamental challenge. Here we report that plant-derived depsipeptide FR900359 (FR) is ideally suited to this task. Using multifaceted approach systematically characterize FR as inhibitor Gq/11/14 over all other mammalian Gα isoforms and elaborate its molecular mechanism action. We also use investigate whether inhibition Gq an effective...
Abstract Endocytosis and intracellular trafficking of receptors are pivotal to maintain physiological functions drug action; however, robust quantitative approaches lacking study such processes in live cells. Here we present new bioluminescence resonance energy transfer (BRET) sensors quantitatively monitor G protein-coupled (GPCRs) β-arrestin trafficking. These based on bystander BRET use the naturally interacting chromophores luciferase (RLuc) green fluorescent protein (rGFP) from Renilla...
We directly examined the role of Ca v 1.3 (α 1D ) 2+ channel in sinoatrial (SA) node by using channel-deficient mice. A previous report has shown that null mutant (Ca −/− mice have sinus bradycardia with a prolonged PR interval. In present study, we show spontaneous action potentials recorded from SA nodes significant decrease beating frequency and rate diastolic depolarization compared their heterozygous +/− or wild-type (WT, +/+ littermates, suggesting deficit is intrinsic to node....
G protein-coupled receptors (GPCRs) are important therapeutic targets that exhibit functional selectivity (biased signaling), in which different ligands or receptor variants elicit distinct downstream signaling. Understanding all the signaling events and biases contribute to both beneficial adverse effects of GPCR stimulation by given is for drug discovery. Here, we report design, validation, use pathway-selective bioluminescence resonance energy transfer (BRET) biosensors monitor engagement...
Abstract In addition to G protein-coupled receptor (GPCR) desensitization and endocytosis, β-arrestin recruitment ligand-stimulated GPCRs promotes non-canonical signalling cascades. Distinguishing the respective contributions of β-arrestin-promoted endocytosis in propagating has been limited by lack selective analytical tools. Here, using a combination virtual screening cell-based assays, we have identified small molecule that selectively inhibits interaction between β2-adaptin subunit...
Abstract Recent studies have shown that G protein coupled receptors (GPCRs) show selective and promiscuous coupling to different Gα subfamilies yet the mechanisms of range preferences remain unclear. Here, we use Molecular Dynamics (MD) simulations on ten GPCR:G complexes location (spatial) duration (temporal) intermolecular contacts at GPCR:Gα interface play a critical role in how GPCRs selectively interact with proteins. We identify some are common across others specific subfamilies. Using...
Previously, D2 dopamine receptors (D2 DARs) have been shown to undergo G-protein-coupled receptor kinase phosphorylation in an agonist-specific fashion. We now investigated the ability of second messenger-activated protein kinases, A (PKA) and C (PKC), mediate desensitization DAR. HEK293T cells were transiently transfected with DAR then treated intracellular activators inhibitors PKA or PKC. Treatment agents that increase cAMP, activate PKA, had no effect on state DAR, suggesting does not...
We investigated the role of G protein-coupled receptor kinase (GRK)-mediated phosphorylation in agonist-induced desensitization, arrestin association, endocytosis, and intracellular trafficking D2 dopamine (DAR). Agonist activation DARs results rapid sustained that is solely mediated by GRKs. A survey GRKs revealed only GRK2 or GRK3 promotes DAR phosphorylation. Mutational analyses resulted identification eight serine/threonine residues within third cytoplasmic loop are phosphorylated...
Pancreatic β cells are the source of insulin, which directly lowers blood glucose levels in body. Our analyses α1D gene-knockout (α1D–/–) mice show that L-type calcium channel, α1D, is required for proper cell generation postnatal pancreas. Knockout were characteristically slightly smaller than their littermates and exhibited hypoinsulinemia intolerance. However, isolated α1D–/– islets persisted sensing insulin secretion, with compensatory overexpression another channel gene, α1C....
Pancreatic β cells are the source of insulin, which directly lowers blood glucose levels in body. Our analyses α1D gene-knockout (α1D–/–) mice show that L-type calcium channel, α1D, is required for proper cell generation postnatal pancreas. Knockout were characteristically slightly smaller than their littermates and exhibited hypoinsulinemia intolerance. However, isolated α1D–/– islets persisted sensing insulin secretion, with compensatory overexpression another channel gene, α1C....
As for all proteins, G protein-coupled receptors (GPCRs) undergo synthesis and maturation within the endoplasmic reticulum (ER). The mechanisms involved in biogenesis trafficking of GPCRs from ER to cell surface are poorly understood, but they may involve interactions with other proteins. We have now identified chaperone protein calnexin as an interacting both D(1) D(2) dopamine receptors. These protein-protein were confirmed using Western blot analysis co-immunoprecipitation experiments. To...
We investigated the regulatory effects of GRK2 on D(2) dopamine receptor signaling and found that this kinase inhibits both expression functional in a phosphorylation-independent manner, apparently through different mechanisms. Overexpression was to suppress at cell surface enhance agonist-induced internalization, whereas short interfering RNA knockdown endogenous led an increase decreased agonist-mediated endocytosis. These were not due GRK2-mediated phosphorylation as phosphorylation-null...
Ligand binding induces conformational changes in FZD 5 , activation of heterotrimeric G proteins, and q -dependent signaling.
Abstract Agonist-induced phosphorylation of G protein-coupled receptors (GPCRs) is a primary determinant β-arrestin (βarr) recruitment and trafficking. For several GPCRs such as the vasopressin receptor subtype 2 (V R), agonist-stimulation first drives translocation βarrs to plasma membrane, followed by endosomal trafficking, which generally considered be orchestrated multiple sites. We have previously shown that mutation single site in V R (i.e., T360A ) results near-complete loss βarr...
G protein–coupled receptors engage both proteins and β-arrestins, their coupling can be biased by ligands mutations. Here, to resolve structural elements mechanisms underlying effector the angiotensin II (AngII) type 1 receptor (AT1R), we combined alanine scanning mutagenesis of entire sequence with pharmacological profiling Gα q β-arrestin engagement mutant molecular dynamics simulations. We showed that AT1R involved a large number residues spread across receptor, whereas fewer regions...
Macrophage mitochondrial dysfunction, caused by oxidative stress, has been proposed as an essential event in the progression of chronic inflammation diseases, such atherosclerosis. The cluster differentiation-36 (CD36) and lectin-like oxLDL receptor-1 (LOX-1) scavenger receptors mediate macrophage uptake oxidized low-density lipoprotein (oxLDL), which contributes to dysfunction sustained production reactive oxygen species (mtROS), well membrane depolarization. In present study, antioxidant...
In comparison to the well characterized role of principal subunit voltage-gated Ca 2+ channels, pore-forming, antagonist-binding α 1 subunit, considerably less is understood about how β subunits contribute neuronal channel function. We studied 3 major in neurons, by using a gene-targeting strategy. The deficient (β −/−) animals were indistinguishable from wild type (wt) with no gross morphological or histological differences. However, sympathetic −/− L- and N-type current was significantly...
A comprehensive understanding of signalling downstream GPCRs requires a broad approach to capture novel modalities in addition established pathways. Here, using an array sixteen validated BRET-based biosensors, we analyzed the ability seven different β-adrenergic ligands engage five distinct pathways β1-adrenergic receptor (β1AR). In generating signatures and capturing functional selectivity for toward these pathways, also revealed coupling that have not previously been ascribed βAR. These...
β-Arrestins are signaling adaptors that bind to agonist-occupied G protein-coupled receptors (GPCRs) and target them for endocytosis; however, the mechanisms regulating receptor/β-arrestin complexes trafficking in endosomes, remain ill defined. Here we show, live cells, differential dynamic regulation of endosomal bradykinin B2 receptor (B2R) with either β-arrestin-1 or -2. We find a novel role MAPK B2R/β-arrestin-2 complex formation, mediated by an ERK1/2 regulatory motif hinge domain rat...
ONC201 is a first-in-class imipridone compound that in clinical trials for the treatment of high-grade gliomas and other advanced cancers. Recent studies identified antagonizes D2-like dopamine receptors at therapeutically relevant concentrations. In current study, characterization using radioligand binding multiple functional assays revealed it was full antagonist D2 D3 (D2R D3R) with low micromolar potencies, similar to its potency antiproliferative effects. Curve-shift experiments...
Abstract Dopaminergic signaling pathways have been extensively investigated using PET imaging, primarily with antagonist radioligands of D 2 and 3 dopamine receptors (DARs). Recently, agonist /D DARs begun to be developed employed. One such is ( R )‐2‐ 11 CH O‐ N‐n ‐propylnorapomorphine (MNPA). Here, we perform a pharmacological characterization MNPA recombinant expressed in HEK293 cells. was found robustly inhibit forskolin‐stimulated cAMP accumulation the same extent as or DAR‐transfected...