Browse
Submit Data
Databases
API
Help

Dataset Information

16 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Local membrane charge regulates ?2 adrenergic receptor coupling to Gi3.

ABSTRACT: The ?2 adrenergic receptor (?2AR) signals through both Gs and Gi in cardiac myocytes, and the Gi pathway counteracts the Gs pathway. However, Gi coupling is much less efficient than Gs coupling in most cell-based and biochemical assays, making it difficult to study ?2AR-Gi interactions. Here we investigate the role of phospholipid composition on Gs and Gi coupling. While negatively charged phospholipids are known to enhance agonist affinity and stabilize an active state of the ?2AR, we find that they impair coupling to Gi3 and facilitate coupling to Gs. Positively charged Ca2+ and Mg2+, known to interact with the negative charge on phospholipids, facilitates Gi3 coupling. Mutational analysis suggests that Ca2+ coordinates an interaction between phospholipid and the negatively charged EDGE motif on the amino terminal helix of Gi3. Taken together, our observations suggest that local membrane charge modulates the interaction between ?2AR and competing G protein subtypes.

SUBMITTER: Strohman MJ

PROVIDER: S-EPMC6527575 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Local membrane charge regulates β2 adrenergic receptor coupling to Gi3.

Strohman M J MJ Maeda S S Hilger D D Masureel M M Du Y Y Kobilka B K BK

Nature communications 20190520 1

The β2 adrenergic receptor (β2AR) signals through both Gs and Gi in cardiac myocytes, and the Gi pathway counteracts the Gs pathway. However, Gi coupling is much less efficient than Gs coupling in most cell-based and biochemical assays, making it difficult to study β2AR-Gi interactions. Here we investigate the role of phospholipid composition on Gs and Gi coupling. ...[more]

PMID: 31110175

Similar Datasets

A high-resolution description of β1-adrenergic receptor functional dynamics and allosteric coupling from backbone NMR.

Project description:Signal transmission and regulation of G-protein-coupled receptors (GPCRs) by extra- and intracellular ligands occurs via modulation of complex conformational equilibria, but their exact kinetic details and underlying atomic mechanisms are unknown. Here we quantified these dynamic equilibria in the β1-adrenergic receptor in its apo form and seven ligand complexes using 1H/15N NMR spectroscopy. We observe three major exchanging conformations: an inactive conformation (Ci), a preactive conformation (Cp) and an active conformation (Ca), which becomes fully populated in a ternary complex with a G protein mimicking nanobody. The Ci ↔ Cp exchange occurs on the microsecond scale, the Cp ↔ Ca exchange is slower than ~5 ms and only occurs in the presence of two highly conserved tyrosines (Y5.58, Y7.53), which stabilize the active conformation of TM6. The Cp→Ca chemical shift changes indicate a pivoting motion of the entire TM6 that couples the effector site to the orthosteric ligand pocket.

| S-EPMC7200737 | biostudies-literature

β1-adrenergic receptor O-glycosylation regulates N-terminal cleavage and signaling responses in cardiomyocytes.

Project description:β1-adrenergic receptors (β1ARs) mediate catecholamine actions in cardiomyocytes by coupling to both Gs/cAMP-dependent and Gs-independent/growth-regulatory pathways. Structural studies of the β1AR define ligand-binding sites in the transmembrane helices and effector docking sites at the intracellular surface of the β1AR, but the extracellular N-terminus, which is a target for post-translational modifications, typically is ignored. This study identifies β1AR N-terminal O-glycosylation at Ser37/Ser41 as a mechanism that prevents β1AR N-terminal cleavage. We used an adenoviral overexpression strategy to show that both full-length/glycosylated β1ARs and N-terminally truncated glycosylation-defective β1ARs couple to cAMP and ERK-MAPK signaling pathways in cardiomyocytes. However, a glycosylation defect that results in N-terminal truncation stabilizes β1ARs in a conformation that is biased toward the cAMP pathway. The identification of O-glycosylation and N-terminal cleavage as novel structural determinants of β1AR responsiveness in cardiomyocytes could be exploited for therapeutic advantage.

| S-EPMC5554155 | biostudies-literature

S-nitrosylation of beta-arrestin regulates beta-adrenergic receptor trafficking.

Project description:Signal transduction through G protein-coupled receptors (GPCRs) is regulated by receptor desensitization and internalization that follow agonist stimulation. Nitric oxide (NO) can influence these processes, but the cellular source of NO bioactivity and the effects of NO on GPCR-mediated signal transduction are incompletely understood. Here, we show in cells and mice that beta-arrestin 2, a central element in GPCR trafficking, interacts with and is S-nitrosylated at a single cysteine by endothelial NO synthase (eNOS), and that S-nitrosylation of beta-arrestin 2 is promoted by endogenous S-nitrosogluthathione. S-nitrosylation after agonist stimulation of the beta-adrenergic receptor, a prototypical GPCR, dissociates eNOS from beta-arrestin 2 and promotes binding of beta-arrestin 2 to clathrin heavy chain/beta-adaptin, thereby accelerating receptor internalization. The agonist- and NO-dependent shift in the affiliations of beta-arrestin 2 is followed by denitrosylation. Thus, beta-arrestin subserves the functional coupling of eNOS and GPCRs, and dynamic S-nitrosylation/denitrosylation of beta-arrestin 2 regulates stimulus-induced GPCR trafficking.

| S-EPMC2630185 | biostudies-literature

SAP97 controls the trafficking and resensitization of the beta-1-adrenergic receptor through its PDZ2 and I3 domains.

Project description:Previous studies have determined that the type-1 PDZ sequence at the extreme carboxy-terminus of the ß1-adrenergic receptor (ß1-AR) binds SAP97 and AKAP79 to organize a scaffold involved in trafficking of the ß1-AR. In this study we focused on characterizing the domains in SAP97 that were involved in recycling and resensitization of the ß1-AR in HEK-293 cells. Using a SAP97 knockdown and rescue strategy, we determined that PDZ-deletion mutants of SAP97 containing PDZ2 rescued the recycling and resensitization of the ß1-AR. Among the three PDZs of SAP97, PDZ2 displayed the highest affinity in binding to the ß1-AR. Expression of isolated PDZ2, but not the other PDZs, inhibited the recycling of the ß1-AR by destabilizing the macromolecular complex involved in trafficking and functional resensitization of the ß1-AR. In addition to its PDZs, SAP97 contains other protein interacting domains, such as the I3 sequence in the SRC homology-3 (SH3) domain, which binds to AKAP79. Deletion of I3 from SAP97 (?I3-SAP97) did not affect the binding of SAP97 to the ß1-AR. However, ?I3-SAP97 could not rescue the recycling of the ß1-AR because it failed to incorporate AKAP79/PKA into the SAP97-ß1-AR complex. Therefore, bipartite binding of SAP97 to the ß1-AR and to AKAP79 is necessary for SAP97-mediated effects on recycling, externalization and functional resensitization of the ß1-AR. These data establish a prominent role for PDZ2 and I3 domains of SAP97 in organizing the ß1-adrenergic receptosome involved in connecting the ß1-AR to trafficking and signaling networks.

| S-EPMC3656048 | biostudies-literature

Lipids and Phosphorylation Conjointly Modulate Complex Formation of β2-Adrenergic Receptor and β-arrestin2.

Project description:G protein-coupled receptors (GPCRs) are the largest class of human membrane proteins that bind extracellular ligands at their orthosteric binding pocket to transmit signals to the cell interior. Ligand binding evokes conformational changes in GPCRs that trigger the binding of intracellular interaction partners (G proteins, G protein kinases, and arrestins), which initiate diverse cellular responses. It has become increasingly evident that the preference of a GPCR for a certain intracellular interaction partner is modulated by a diverse range of factors, e.g., ligands or lipids embedding the transmembrane receptor. Here, by means of molecular dynamics simulations of the β2-adrenergic receptor and β-arrestin2, we study how membrane lipids and receptor phosphorylation regulate GPCR-arrestin complex conformation and dynamics. We find that phosphorylation drives the receptor's intracellular loop 3 (ICL3) away from a native negatively charged membrane surface to interact with arrestin. If the receptor is embedded in a neutral membrane, the phosphorylated ICL3 attaches to the membrane surface, which widely opens the receptor core. This opening, which is similar to the opening in the G protein-bound state, weakens the binding of arrestin. The loss of binding specificity is manifested by shallower arrestin insertion into the receptor core and higher dynamics of the receptor-arrestin complex. Our results show that receptor phosphorylation and the local membrane composition cooperatively fine-tune GPCR-mediated signal transduction. Moreover, the results suggest that deeper understanding of complex GPCR regulation mechanisms is necessary to discover novel pathways of pharmacological intervention.

| S-EPMC8733679 | biostudies-literature

Components of the Gs signaling cascade exhibit distinct changes in mobility and membrane domain localization upon β2 -adrenergic receptor activation.

Project description:The G protein signaling cascade is a key player in cell signaling. Cascade activation leads to a redistribution of its members in various cellular compartments. These changes are likely related to the "second wave" of signaling from endosomes. Here, we set out to determine whether Gs signaling cascade members expressed at very low levels exhibit altered mobility and localize in clathrin-coated structures (CCSs) or caveolae upon activation by β2 -adrenergic receptors (β2 AR). Activated β2 AR showed decreased mobility and sustained accumulation in CCSs but not in caveolae. Arrestin 3 translocated to the plasma membrane after β2 AR activation and showed very low mobility and pronounced accumulation in CCSs. In contrast, Gαs and Gγ2 exhibited a modest reduction in mobility but no detectable accumulation in or exclusion from CCSs or caveolae. The effector adenylyl cyclase 5 (AC5) showed a slight mobility increase upon β2 AR stimulation, no redistribution to CCSs, and weak activation-independent accumulation in caveolae. Our findings show an overall decrease in the mobility of most activated Gs signaling cascade members and confirm that β2 AR and arrestin 3 accumulate in CCSs, while Gαs , Gγ2 and AC5 can transiently enter CCSs and caveolae but do not accumulate in and are not excluded from these domains.

| S-EPMC7333016 | biostudies-literature

Adiponectin up-regulates the decrease of myocardial autophagic flux induced by β1 -adrenergic receptor autoantibody partly dependent on AMPK.

Project description:Cardiomyocytes autophagy is essential for maintaining cardiac function. Our previous studies have found that β1 -adrenergic receptor autoantibody (β1 -AA) induced the decreased myocardial autophagic flux, which resulted in cardiomyocyte death and cardiac dysfunction. And other studies demonstrated that β1 -AA induced the decrease of AMPK phosphorylation, the key hub of autophagy pathway, while adiponectin up-regulated autophagic flux mediated by AMPK. However, it is not clear whether adiponectin improves the inhibition of myocardial autophagic flux induced by β1 -AA by up-regulating the level of AMPK phosphorylation. In this study, it has been confirmed that β1 -AA induced the decrease of AMPK phosphorylation level in both vivo and vitro. Moreover, pretreatment of cardiomyocytes with AMPK inhibitor Compound C could further reduce the autophagic flux induced by β1 -AA. Adiponectin deficiency could aggravate the decrease of myocardial AMPK phosphorylation level, autophagic flux and cardiac function induced by β1 -AA. Further, exogenous adiponectin could reverse the decline of AMPK phosphorylation level and autophagic flux induced by β1 -AA and even reduce cardiomyocyte death. While pretreated with the Compound C, the adiponectin treatment did not improve the decreased autophagosome formation, but still improved the decreased autophagosome clearance induced by β1 -AA in cardiomyocytes. This study is the first time to confirm that β1 -AA could inhibit myocardial autophagic flux by down-regulating AMPK phosphorylation level. Adiponectin could improve the inhibition of myocardial autophagic flux induced by β1 -AA partly dependent on AMPK, so as to provide an experimental basis for the treatment of patients with β1 -AA-positive cardiac dysfunction.

| S-EPMC8419161 | biostudies-literature

β2-adrenergic receptor promotes liver regeneration partially through crosstalk with c-met.

Project description:The β2-adrenergic receptor (β2AR) is a G protein-coupled receptor (GPCR) that mediates the majority of cellular responses to external stimuli. Aberrant expression of β2AR results in various pathophysiological disorders, including tumorigenesis, but little is known about its role in liver regeneration. This study aims to investigate the impact and the underlying mechanism of β2AR in liver regeneration. Here, we found that β2AR was upregulated during liver regeneration induced by 70% PH. Deletion of β2AR in mice resulted in 62% mortality 2 days post-PH, decreased proliferative marker expression and impaired liver function throughout regeneration. Moreover, AAV8-mediated overexpression of β2AR in hepatocytes accelerated the regeneration process and increased target gene expression. Mechanistically, β2AR recruited G-protein-coupled receptor kinase 2 (GRK2) to the membrane and then formed a complex with c-met to transactivate c-met signaling, which triggered downstream extracellular regulated protein kinase (ERK) signaling activation and nuclear translocation. Inhibition of c-met with SU11274 or ERK with U0126 decreased β2AR overexpression-induced hepatocyte proliferation. Our findings revealed that β2AR might act as a critical mediator regulating liver regeneration by crosstalk with c-met and activation of ERK signaling.

| S-EPMC9237079 | biostudies-literature

Increased circulating β2-adrenergic receptor autoantibodies are associated with smoking-related emphysema.

Project description:Smoking is a dominant risk factor for chronic obstructive pulmonary disease (COPD) and emphysema, but not every smoker develops emphysema. Immune responses in smokers vary. Some autoantibodies have been shown to contribute to the development of emphysema in smokers. β2-adrenergic receptors (β2-ARs) are important targets in COPD therapy. β2-adrenergic receptor autoantibodies (β2-AAbs), which may directly affect β2-ARs, were shown to be increased in rats with passive-smoking-induced emphysema in our current preliminary studies. Using cigarette-smoke exposure (CS-exposure) and active-immune (via injections of β2-AR second extracellular loop peptides) rat models, we found that CS-exposed rats showed higher serum β2-AAb levels than control rats before alveolar airspaces became enlarged. Active-immune rats showed increased serum β2-AAb levels, and exhibited alveolar airspace destruction. CS-exposed-active-immune treated rats showed more extensive alveolar airspace destruction than rats undergoing CS-exposure alone. In our current clinical studies, we showed that plasma β2-AAb levels were positively correlated with the RV/TLC (residual volume/total lung capacity) ratio (r = 0.455, p < 0.001) and RV%pred (residual volume/residual volume predicted percentage, r = 0.454, p < 0.001) in 50 smokers; smokers with higher plasma β2-AAb levels exhibited worse alveolar airspace destruction. We suggest that increased circulating β2-AAbs are associated with smoking-related emphysema.

| S-EPMC5338268 | biostudies-literature

α2-Adrenergic Disruption of β Cell BDNF-TrkB Receptor Tyrosine Kinase Signaling.

Project description:Adrenergic signaling is a well-known input into pancreatic islet function. Specifically, the insulin-secreting islet β cell expresses the Gi/o-linked α2-adrenergic receptor, which upon activation suppresses insulin secretion. The use of the adrenergic agonist epinephrine at micromolar doses may have supraphysiological effects. We found that pretreating β cells with micromolar concentrations of epinephrine differentially inhibited activation of receptor tyrosine kinases. We chose TrkB as an example because of its relative sensitivity to the effects of epinephrine and due to its potential regulatory role in the β cell. Our characterization of brain-derived neurotrophic factor (BDNF)-TrkB signaling in MIN6 β cells showed that TrkB is activated by BDNF as expected, leading to canonical TrkB autophosphorylation and subsequent downstream signaling, as well as chronic effects on β cell growth. Micromolar, but not nanomolar, concentrations of epinephrine blocked BDNF-induced TrkB autophosphorylation and downstream mitogen-activated protein kinase pathway activation, suggesting an inhibitory phenomenon at the receptor level. We determined epinephrine-mediated inhibition of TrkB activation to be Gi/o-dependent using pertussis toxin, arguing against an off-target effect of high-dose epinephrine. Published data suggested that inhibition of potassium channels or phosphoinositide-3-kinase signaling may abrogate the negative effects of epinephrine; however, these did not rescue TrkB signaling in our experiments. Taken together, these results show that (1) TrkB kinase signaling occurs in β cells and (2) use of epinephrine in studies of insulin secretion requires careful consideration of concentration-dependent effects. BDNF-TrkB signaling in β cells may underlie pro-survival or growth signaling and warrants further study.

| S-EPMC7593622 | biostudies-literature