Metalloprotease cleavage of the N terminus of the orphan G protein–coupled receptor GPR37L1 reduces its constitutive activity

2016 ◽  
Vol 9 (423) ◽  
pp. ra36-ra36 ◽  
Author(s):  
James L. J. Coleman ◽  
Tony Ngo ◽  
Johannes Schmidt ◽  
Nadine Mrad ◽  
Chu Kong Liew ◽  
...  
Keyword(s):  
G Protein ◽  
Cultured Cells ◽  
Amino Terminus ◽  
Wild Type ◽  
Guanine Nucleotide Binding Protein ◽  
Inactive Form ◽  
In The Wild ◽  
Reporter Assays ◽  
Guanine Nucleotide Binding ◽  
G Protein Coupled

Little is known about the pharmacology or physiology of GPR37L1, a G protein (heterotrimeric guanine nucleotide–binding protein)–coupled receptor that is abundant in the cerebellum. Mice deficient in this receptor exhibit precocious cerebellar development and hypertension. We showed that GPR37L1 coupled to the G protein Gαs when heterologously expressed in cultured cells in the absence of any added ligand, whereas a mutant receptor that lacked the amino terminus was inactive. Conversely, inhibition of ADAMs (a disintegrin and metalloproteases) enhanced receptor activity, indicating that the presence of the amino terminus is necessary for GPR37L1 signaling. Metalloprotease-dependent processing of GPR37L1 was evident in rodent cerebellum, where we detected predominantly the cleaved, inactive form. However, comparison of the accumulation of cAMP (adenosine 3′,5′-monophosphate) in response to phosphodiesterase inhibition in cerebellar slice preparations from wild-type and GPR37L1-null mice showed that some constitutive signaling remained in the wild-type mice. In reporter assays of Gαs or Gαi signaling, the synthetic, prosaposin-derived peptide prosaptide (TX14A) did not increase GPR37L1 activity. Our data indicate that GPR37L1 may be a constitutively active receptor, or perhaps its ligand is present under the conditions that we used for analysis, and that the activity of this receptor is instead controlled by signals that regulate metalloprotease activity in the tissue.

scholarly journals The G-protein coupled receptor SRX-97 is required for concentration dependent sensing of Benzaldehyde in Caenorhabditis elegans

2020 ◽  
Author(s):  
Nagesh Y. Kadam ◽  
Sukanta Behera ◽  
Sandeep Kumar ◽  
Anindya Ghosh-Roy ◽  
Kavita Babu
Keyword(s):  
G Protein ◽  
Olfactory System ◽  
Olfactory Receptors ◽  
Guanine Nucleotide Binding Protein ◽  
C Elegans ◽  
Multiple Receptors ◽  
Genes Encoding ◽  
High Concentrations ◽  
Guanine Nucleotide Binding ◽  
G Protein Coupled

AbstractThe G-protein (heterotrimeric guanine nucleotide–binding protein)–coupled receptors in the olfactory system function to sense the surroundings and respond to various odorants. The genes encoding for the olfactory receptors in C. elegans are larger in number in comparison to those in mammals, suggesting complexity in the receptor– odorant relationships. Recent studies have shown that the same odorant in different concentration could act on multiple receptors in different neurons to induce attractive or repulsive responses. The ASH neuron is known to be responsible for responding to high concentrations of volatile odorants. Here we characterize a new GPCR, SRX-97. We found that the srx-97 promoter shows expression specifically in the head ASH and tail PHB chemosensory neurons of C. elegans. Further, the SRX-97 protein localizes to the ciliary ends of the ASH neurons. Analysis of CRISPR/based deletion mutants of the srx-97 gene suggest that this gene is involved in the recognition of high concentrations of benzaldehyde. This was further confirmed through rescue and neuronal ablation experiments. Our work gives insight into concentration dependent receptor function in the olfactory system and provides details of an additional molecule that could help the animal navigate its surroundings.

scholarly journals Noncanonical scaffolding of Gαi and β-arrestin by G protein–coupled receptors

Science ◽  
2021 ◽  
pp. eaay1833
Author(s):  
Jeffrey S. Smith ◽  
Thomas F. Pack ◽  
Asuka Inoue ◽  
Claudia Lee ◽  
Kevin Zheng ◽  
...  
Keyword(s):  
G Protein ◽  
Drug Targets ◽  
Direct Interaction ◽  
Adaptor Proteins ◽  
G Protein Coupled Receptors ◽  
Guanine Nucleotide Binding Protein ◽  
Signaling Mechanism ◽  
Protein Activation ◽  
Guanine Nucleotide Binding ◽  
G Protein Coupled

Heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors (GPCRs) are common drug targets and canonically couple to specific Gα protein subtypes and β-arrestin adaptor proteins. G protein- and β-arrestin-mediated signaling have been considered separable. We show GPCRs promote a direct interaction between Gαi protein subtype family members and β-arrestins, regardless of their canonical Gαi protein subtype coupling. Gαi:β-arrestin complexes bound extracellular signal-regulated kinase (ERK) and their disruption impaired both ERK activation and cell migration, consistent with β-arrestins requiring a functional interaction with Gαi for certain signaling events. These results introduce a GPCR signaling mechanism distinct from canonical G protein activation in which GPCRs cause the formation of Gαi:β-arrestin signaling complexes.

Mapping the Heart

2010 ◽  
Vol 18 (4) ◽  
pp. 6-8
Author(s):  
Stephen W. Carmichael
Keyword(s):  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
G Protein Coupled Receptors ◽  
Receptor Subtypes ◽  
Cardiac Muscle Cells ◽  
Guanine Nucleotide Binding Protein ◽  
The Common ◽  
Guanine Nucleotide Binding ◽  
First Time ◽  
G Protein Coupled

Some of the receptors on the surface of cardiac muscle cells (cardiomyocytes) mediate the response of these cells to catecholamines by causing the production of the common second messenger cyclic adenosine monophosphate (cAMP). An example of such receptors are the β1- and β2-adrenergic receptors (βARs) that are heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors. Selective stimulation of these two receptor subtypes leads to distinct physiological and pathophysiological responses, but their precise location on the surface of cardiomyocytes has not been correlated with these responses. In an ingenious combination of techniques, Viacheslav Nikolaev, Alexey Moshkov, Alexander Lyon, Michele Miragoli, Pavel Novak, Helen Paur, Martin Lohse, Yuri Korchev, Sian Harding, and Julia Gorelik have mapped the function of these receptors for the first time.

Transmembrane prolyl 4-hydroxylase is a fourth prolyl 4-hydroxylase regulating EPO production and erythropoiesis

Blood ◽  
2012 ◽  
Vol 120 (16) ◽  
pp. 3336-3344 ◽  
Author(s):  
Anu Laitala ◽  
Ellinoora Aro ◽  
Gail Walkinshaw ◽  
Joni M. Mäki ◽  
Maarit Rossi ◽  
...  
Keyword(s):  
Cultured Cells ◽  
Mrna Level ◽  
Hypoxia Inducible Factor ◽  
Mrna Levels ◽  
Wild Type ◽  
Α Subunit ◽  
Hepcidin Expression ◽  
In The Wild ◽  
Hepcidin Mrna

AbstractAn endoplasmic reticulum transmembrane prolyl 4-hydroxylase (P4H-TM) is able to hydroxylate the α subunit of the hypoxia-inducible factor (HIF) in vitro and in cultured cells, but nothing is known about its roles in mammalian erythropoiesis. We studied such roles here by administering a HIF-P4H inhibitor, FG-4497, to P4h-tm−/− mice. This caused larger increases in serum Epo concentration and kidney but not liver Hif-1α and Hif-2α protein and Epo mRNA levels than in wild-type mice, while the liver Hepcidin mRNA level was lower in the P4h-tm−/− mice than in the wild-type. Similar, but not identical, differences were also seen between FG-4497–treated Hif-p4h-2 hypomorphic (Hif-p4h-2gt/gt) and Hif-p4h-3−/− mice versus wild-type mice. FG-4497 administration increased hemoglobin and hematocrit values similarly in the P4h-tm−/− and wild-type mice, but caused higher increases in both values in the Hif-p4h-2gt/gt mice and in hematocrit value in the Hif-p4h-3−/− mice than in the wild-type. Hif-p4h-2gt/gt/P4h-tm−/− double gene-modified mice nevertheless had increased hemoglobin and hematocrit values without any FG-4497 administration, although no such abnormalities were seen in the Hif-p4h-2gt/gt or P4h-tm−/− mice. Our data thus indicate that P4H-TM plays a role in the regulation of EPO production, hepcidin expression, and erythropoiesis.

CCK receptor phosphorylation exposes regulatory domains affecting phosphorylation and receptor trafficking

2000 ◽  
Vol 279 (6) ◽  
pp. C1986-C1992 ◽  
Author(s):  
Rammohan V. Rao ◽  
Eileen L. Holicky ◽  
Susan M. Kuntz ◽  
Laurence J. Miller
Keyword(s):  
G Protein ◽  
Chinese Hamster ◽  
G Protein Coupled Receptors ◽  
Receptor Internalization ◽  
Ovary Cell ◽  
Guanine Nucleotide Binding Protein ◽  
Receptor Phosphorylation ◽  
Regulatory Domains ◽  
Ovary Cell Line ◽  
G Protein Coupled

Agonist-stimulated phosphorylation of guanine nucleotide-binding protein (G protein)-coupled receptors has been recognized as an important mechanism for desensitization by interfering with coupling of the activated receptor with its G protein. We recently described a mutant of the CCK receptor that modified two of five key sites of phosphorylation (S260,264A) and eliminated agonist-stimulated receptor phosphorylation, despite normal ligand binding and signaling (20). As expected, this nonphosphorylated mutant had impaired rapid desensitization but was ultimately able to be desensitized by normal receptor internalization. Here we demonstrate that this mutant receptor is also defective in resensitization, with abnormal recycling to the cell surface. To explore this, another receptor mutant was prepared, replacing the same serines with aspartates to mimic the charge of serine-phosphate (S260,264D). This mutant was expressed in a Chinese hamster ovary cell line and shown to bind CCK normally. It had accelerated kinetics of signaling and desensitization and was phosphorylated in response to agonist occupation, with all other normal sites of phosphorylation modified. It was internalized like wild-type receptors and was resensitized and trafficked normally. This provides evidence for an additional important function for phosphorylation of G protein-coupled receptors. Phosphorylation may induce a conformational change in the receptor to expose other potential sites of phosphorylation and to expose domains involved in the targeting and trafficking of endosomes. The hierarchical phosphorylation of these sites may play a key role in receptor regulation.

scholarly journals Rescue of defective G protein–coupled receptor function in vivo by intermolecular cooperation

2010 ◽  
Vol 107 (5) ◽  
pp. 2319-2324 ◽  
Author(s):  
Adolfo Rivero-Müller ◽  
Yen-Yin Chou ◽  
Inhae Ji ◽  
Svetlana Lajic ◽  
Aylin C. Hanyaloglu ◽  
...  
Keyword(s):  
G Protein ◽  
G Protein Coupled Receptors ◽  
Luteinizing Hormone Receptor ◽  
Wild Type ◽  
Gpcr Signaling ◽  
Physiological Relevance ◽  
Biosynthesis Activation ◽  
Mutant Receptors ◽  
G Protein Coupled

G protein–coupled receptors (GPCRs) are ubiquitous mediators of signaling of hormones, neurotransmitters, and sensing. The old dogma is that a one ligand/one receptor complex constitutes the functional unit of GPCR signaling. However, there is mounting evidence that some GPCRs form dimers or oligomers during their biosynthesis, activation, inactivation, and/or internalization. This evidence has been obtained exclusively from cell culture experiments, and proof for the physiological significance of GPCR di/oligomerization in vivo is still missing. Using the mouse luteinizing hormone receptor (LHR) as a model GPCR, we demonstrate that transgenic mice coexpressing binding-deficient and signaling-deficient forms of LHR can reestablish normal LH actions through intermolecular functional complementation of the mutant receptors in the absence of functional wild-type receptors. These results provide compelling in vivo evidence for the physiological relevance of intermolecular cooperation in GPCR signaling.

Abstract 213: Rapid Activation of G-Protein Coupled Estrogen Receptor 1 Protects the Heart Against Ischemia-Reperfusion Injury by Inhibiting the mPTP Opening via PKC/AKT/ERK/GSK-3b Pathways

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Jean Chrisostome Bopassa ◽  
Rong Lu ◽  
Harpreet Singh ◽  
Netanel F Zilberstein ◽  
Bjorn Olde ◽  
...  
Keyword(s):  
Infarct Size ◽  
G Protein ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Wild Type ◽  
Mptp Opening ◽  
Estrogen Effects ◽  
Estrogen Effect ◽  
Rapid Activation ◽  
G Protein Coupled

Introduction: Estrogen effect can be mediated by three receptors: Classical estrogen receptors: alpha (ERa) and beta (ERb), and recently identified G protein-coupled estrogen receptor1 (GPER1). Hypothesis: We investigated the role of ERa, ERb and GPER1 in mediating rapid estrogen-induced cardioprotection in male mice hearts subjected to ischemia/reperfusion using wild type (WT) and gene specific knockout animals. Methods: Isolated hearts from wild type (WT: C57BL/6NCrL), ERa-/-, ERb-/- and GPER1-/- were perfused using Langendorff apparatus with Krebs Henseleit buffer (control) or with the addition of estrogen (40 nM). Hearts were subjected to 18 min global ischemia followed by 60 min reperfusion. Cardiac function was recorded during the entire experiment and myocardial infarct size measured by TTC staining at the end of the reperfusion. Mitochondria calcium retention capacity (CRC) required to induce the mitochondrial permeability transition pore (mPTP) opening was assessed after 10 min reperfusion. Protein levels were measured by Western Blot in whole heart lysates after 5 min treatment just before ischemia, and after 10 min reperfusion. LY294002, U0126 and Chelerythrin-Cl were used as inhibitor of PI-3K/Akt, MAPK/ERK and PKC translocation, respectively. Results: In WT, ERa-/- and ERb-/-, estrogen treatment significantly improved cardiac functional recovery, reduced infarct size and improved mitochondrial CRC. However, estrogen effects were completely absent in GPER1-/-. Estrogen treatment during 5 min before ischemia induced up-regulation of Akt, GSK-3b, and ERK1/2 phosphorylation in WT mouse as compared with control but not in GPER1-/-. However, after 10 min reperfusion estrogen effect was still oserved on GSK-3b, but not on Akt and ERK1/2. Chelerythrin-Cl prevented estrogen-induced cardioprotection effect and U126 abolished estrogen effect on mitochondrial CRC while LY294002 could not prevent estrogen effect on GSK-3b observed in WT. P<0.05 and n=3-6. Conclusion: Rapid activation of GPER1 induces cardioprotection effect against ischemia/reperfusion injury. Estrogen effects through GPER1 are associated with phosphorylation of Akt, GSK-3b and ERK1/2, translocation of PKC, and inhibition of the mPTP opening.

scholarly journals Melatonin promotes sleep by activating the BK channel in C. elegans

2020 ◽  
Vol 117 (40) ◽  
pp. 25128-25137
Author(s):  
Longgang Niu ◽  
Yan Li ◽  
Pengyu Zong ◽  
Ping Liu ◽  
Yuan Shui ◽  
...  
Keyword(s):  
G Protein ◽  
Neurotransmitter Release ◽  
Expression System ◽  
Molecular Target ◽  
Bk Channel ◽  
G Protein Coupled Receptors ◽  
Wild Type ◽  
Heterologous Expression System ◽  
C Elegans ◽  
G Protein Coupled

Melatonin (Mel) promotes sleep through G protein-coupled receptors. However, the downstream molecular target(s) is unknown. We identified the Caenorhabditis elegans BK channel SLO-1 as a molecular target of the Mel receptor PCDR-1-. Knockout of pcdr-1, slo-1, or homt-1 (a gene required for Mel synthesis) causes substantially increased neurotransmitter release and shortened sleep duration, and these effects are nonadditive in double knockouts. Exogenous Mel inhibits neurotransmitter release and promotes sleep in wild-type (WT) but not pcdr-1 and slo-1 mutants. In a heterologous expression system, Mel activates the human BK channel (hSlo1) in a membrane-delimited manner in the presence of the Mel receptor MT1 but not MT2. A peptide acting to release free Gβγ also activates hSlo1 in a MT1-dependent and membrane-delimited manner, whereas a Gβλ inhibitor abolishes the stimulating effect of Mel. Our results suggest that Mel promotes sleep by activating the BK channel through a specific Mel receptor and Gβλ.

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