scholarly journals Estrogen Signaling Characteristics of Atlantic Croaker G Protein-Coupled Receptor 30 (GPR30) and Evidence It Is Involved in Maintenance of Oocyte Meiotic Arrest

Endocrinology ◽  
2008 ◽  
Vol 149 (7) ◽  
pp. 3410-3426 ◽  
Author(s):  
Yefei Pang ◽  
Jing Dong ◽  
Peter Thomas
Keyword(s):  
G Protein ◽  
Plasma Membranes ◽  
Critical Role ◽  
Hek293 Cells ◽  
Atlantic Croaker ◽  
Estrogen Signaling ◽  
G Protein Coupled Receptor ◽  
Meiotic Arrest ◽  
Transfected Cells ◽  
G Protein Coupled

Human G protein-coupled receptor 30 (GPR30) mediates estradiol-17β (E2) activation of adenylyl cyclase in breast cancer cells and displays E2 binding typical of membrane estrogen receptors (mERs). We identified a mER in Atlantic croaker ovaries with characteristics similar to those of human GPR30. To confirm the proposed role of GPR30 as a mER in this distantly related vertebrate group, we cloned GPR30 from croaker ovaries and examined its distribution, steroid binding, and signaling characteristics. Western blot analysis showed the GPR30 protein (∼40 kDa) is expressed on the plasma membranes of croaker oocytes and HEK293 cells stably transfected with GPR30 cDNA. Plasma membranes prepared from croaker GPR30-transfected cells displayed high-affinity, limited-capacity, and displaceable binding specific for estrogens, characteristic of mERs. Consistent with previous findings with human GPR30, estrogen treatment of plasma membranes from both croaker ovaries and GPR30-transfected cells caused activation of a stimulatory G protein (Gs) resulting in increased cAMP production. Treatment with E2 as well as G-1, a specific GPR30 ligand, significantly reduced both spontaneous and progestin-induced maturation of both croaker and zebrafish oocytes in vitro, suggesting a possible involvement of GPR30 in maintaining oocyte meiotic arrest in these species. Injection of antisense oligonucleotides to GPR30 into zebrafish oocytes blocked the inhibitory effects of estrogen on oocyte maturation, confirming a role for GPR30 in the control of meiotic arrest. These findings further support our previous suggestion that GPR30 is a vertebrate mER. In addition, the results suggest GRP30 may play a critical role in regulating reentry into the meiotic cell cycle in fish oocytes.

A generic microfluidic biosensor of G protein-coupled receptor activation – impedance measurements of reversible morphological changes of reverse transfected HEK293 cells on microelectrodes

RSC Advances ◽  
2015 ◽  
Vol 5 (65) ◽  
pp. 52563-52570 ◽  
Author(s):  
Saurabh K. Srivastava ◽  
Rajesh Ramaneti ◽  
Margriet Roelse ◽  
Hien Duy Tong ◽  
Elwin X. Vrouwe ◽  
...  
Keyword(s):  
G Protein ◽  
Morphological Changes ◽  
Receptor Activation ◽  
Membrane Receptors ◽  
Hek293 Cells ◽  
G Protein Coupled Receptor ◽  
Impedance Measurements ◽  
Transfected Cells ◽  
Microfluidic Biosensor ◽  
G Protein Coupled

Flowcell with micro-IDEs (250–500 μm) covered with both stable and reverse transfected cells overexpressing membrane receptors to demonstrate impedance responses to serial injections of analyte.

scholarly journals Serine 129 phosphorylation of membrane-associated α-synuclein modulates dopamine transporter function in a G protein–coupled receptor kinase–dependent manner

2013 ◽  
Vol 24 (11) ◽  
pp. 1649-1660 ◽  
Author(s):  
Susumu Hara ◽  
Shigeki Arawaka ◽  
Hiroyasu Sato ◽  
Youhei Machiya ◽  
Can Cui ◽  
...  
Keyword(s):  
Cell Surface ◽  
G Protein ◽  
Dopamine Transporter ◽  
Surface Expression ◽  
Hek293 Cells ◽  
Cell Surface Expression ◽  
Receptor Kinase ◽  
Wild Type ◽  
G Protein Coupled Receptor ◽  
G Protein Coupled

Most α-synuclein (α-syn) deposited in Lewy bodies, the pathological hallmark of Parkinson disease (PD), is phosphorylated at Ser-129. However, the physiological and pathological roles of this modification are unclear. Here we investigate the effects of Ser-129 phosphorylation on dopamine (DA) uptake in dopaminergic SH-SY5Y cells expressing α-syn. Subcellular fractionation of small interfering RNA (siRNA)–treated cells shows that G protein–coupled receptor kinase 3 (GRK3), GRK5, GRK6, and casein kinase 2 (CK2) contribute to Ser-129 phosphorylation of membrane-associated α-syn, whereas cytosolic α-syn is phosphorylated exclusively by CK2. Expression of wild-type α-syn increases DA uptake, and this effect is diminished by introducing the S129A mutation into α-syn. However, wild-type and S129A α-syn equally increase the cell surface expression of dopamine transporter (DAT) in SH-SY5Y cells and nonneuronal HEK293 cells. In addition, siRNA-mediated knockdown of GRK5 or GRK6 significantly attenuates DA uptake without altering DAT cell surface expression, whereas knockdown of CK2 has no effect on uptake. Taken together, our results demonstrate that membrane-associated α-syn enhances DA uptake capacity of DAT by GRKs-mediated Ser-129 phosphorylation, suggesting that α-syn modulates intracellular DA levels with no functional redundancy in Ser-129 phosphorylation between GRKs and CK2.

Estrogen Signaling through the Transmembrane G Protein–Coupled Receptor GPR30

2008 ◽  
Vol 70 (1) ◽  
pp. 165-190 ◽  
Author(s):  
Eric R. Prossnitz ◽  
Jeffrey B. Arterburn ◽  
Harriet O. Smith ◽  
Tudor I. Oprea ◽  
Larry A. Sklar ◽  
...  
Keyword(s):  
G Protein ◽  
Estrogen Signaling ◽  
G Protein Coupled Receptor ◽  
G Protein Coupled

scholarly journals Human G protein-coupled receptor 30 is N-glycosylated and N-terminal domain asparagine 44 is required for receptor structure and activity

2019 ◽  
Vol 39 (2) ◽  
Author(s):  
Ernesto Gonzalez de Valdivia ◽  
Caroline Sandén ◽  
Robin Kahn ◽  
Björn Olde ◽  
L.M. Fredrik Leeb-Lundberg
Keyword(s):  
Estrogen Receptor ◽  
G Protein ◽  
Hek293 Cells ◽  
G Protein Coupled Receptor ◽  
Hek 293 ◽  
Receptor Structure ◽  
Terminal Domain ◽  
Endocytic Vesicles ◽  
G Protein Coupled ◽  
Structure And Activity

Abstract G protein-coupled receptor 30 (GPR30), or G protein-coupled estrogen receptor (GPER), is a G protein-coupled receptor (GPCR) that is currently attracting considerable attention in breast cancer and cardiometabolic regulation. The receptor was reported to be a novel membrane estrogen receptor mediating rapid non-genomic responses. However, questions remain about both the cognate ligand and the subcellular localization of receptor activity. Here, we used human embryonic kidney (HEK) 293 (HEK293) cells ectopically expressing N-terminally FLAG-tagged human GPR30 and three unique antibodies (Ab) specifically targetting the receptor N-terminal domain (N-domain) to investigate the role of N-glycosylation in receptor maturation and activity, the latter assayed by constitutive receptor-stimulated extracellular-regulated protein kinase (ERK) 1/2 (ERK1/2) activity. GPR30 expression was complex with receptor species spanning from approximately 40 kDa to higher molecular masses and localized in the endoplasmatic reticulum (ER), the plasma membrane (PM), and endocytic vesicles. The receptor contains three conserved asparagines, Asn25, Asn32, and Asn44, in consensus N-glycosylation motifs, all in the N-domain, and PNGase F treatment showed that at least one of them is N-glycosylated. Mutating Asn44 to isoleucine inactivated the receptor, yielding a unique receptor species at approximately 20 kDa that was recognized by Ab only in a denatured state. On the other hand, mutating Asn25 or Asn32 either individually or in combination, or truncating successively N-domain residues 1–42, had no significant effect either on receptor structure, maturation, or activity. Thus, Asn44 in the GPR30 N-domain is required for receptor structure and activity, whereas N-domain residues 1–42, including specifically Asn25 and Asn32, do not play any major structural or functional role(s).

scholarly journals The Xenopus laevis Isoform of G Protein-Coupled Receptor 3 (GPR3) Is a Constitutively Active Cell Surface Receptor that Participates in Maintaining Meiotic Arrest in X. laevis Oocytes

2008 ◽  
Vol 22 (8) ◽  
pp. 1853-1865 ◽  
Author(s):  
James Deng ◽  
Stephanie Lang ◽  
Christopher Wylie ◽  
Stephen R. Hammes
Keyword(s):  
Cell Surface ◽  
Xenopus Laevis ◽  
G Protein ◽  
Oocyte Maturation ◽  
Cell Surface Receptor ◽  
Xenopus Laevis Oocytes ◽  
Intracellular Camp ◽  
G Protein Coupled Receptor ◽  
Meiotic Arrest ◽  
G Protein Coupled

Abstract Oocytes are held in meiotic arrest in prophase I until ovulation, when gonadotropins trigger a subpopulation of oocytes to resume meiosis in a process termed “maturation.” Meiotic arrest is maintained through a mechanism whereby constitutive cAMP production exceeds phosphodiesterase-mediated degradation, leading to elevated intracellular cAMP. Studies have implicated a constitutively activated Gαs-coupled receptor, G protein-coupled receptor 3 (GPR3), as one of the molecules responsible for maintaining meiotic arrest in mouse oocytes. Here we characterized the signaling and functional properties of GPR3 using the more amenable model system of Xenopus laevis oocytes. We cloned the X. laevis isoform of GPR3 (XGPR3) from oocytes and showed that overexpressed XGPR3 elevated intraoocyte cAMP, in large part via Gβγ signaling. Overexpressed XGPR3 suppressed steroid-triggered kinase activation and maturation of isolated oocytes, as well as gonadotropin-induced maturation of follicle-enclosed oocytes. In contrast, depletion of XGPR3 using antisense oligodeoxynucleotides reduced intracellular cAMP levels and enhanced steroid- and gonadotropin-mediated oocyte maturation. Interestingly, collagenase treatment of Xenopus oocytes cleaved and inactivated cell surface XGPR3, which enhanced steroid-triggered oocyte maturation and activation of MAPK. In addition, human chorionic gonadotropin-treatment of follicle-enclosed oocytes triggered metalloproteinase-mediated cleavage of XGPR3 at the oocyte cell surface. Together, these results suggest that GPR3 moderates the oocyte response to maturation-promoting signals, and that gonadotropin-mediated activation of metalloproteinases may play a partial role in sensitizing oocytes for maturation by inactivating constitutive GPR3 signaling.

scholarly journals Inhibition of Ebola and Marburg Virus Entry by G Protein-Coupled Receptor Antagonists

2015 ◽  
Vol 89 (19) ◽  
pp. 9932-9938 ◽  
Author(s):  
Han Cheng ◽  
Calli M. Lear-Rooney ◽  
Lisa Johansen ◽  
Elizabeth Varhegyi ◽  
Zheng W. Chen ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
G Protein ◽  
High Mortality ◽  
Ebola Virus ◽  
Critical Role ◽  
Marburg Virus ◽  
Severe Illness ◽  
G Protein Coupled Receptor ◽  
Chemical Library ◽  
G Protein Coupled

ABSTRACTFiloviruses, consisting of Ebola virus (EBOV) and Marburg virus (MARV), are among the most lethal infectious threats to mankind. Infections by these viruses can cause severe hemorrhagic fevers in humans and nonhuman primates with high mortality rates. Since there is currently no vaccine or antiviral therapy approved for humans, there is an urgent need to develop prophylactic and therapeutic options for use during filoviral outbreaks and bioterrorist attacks. One of the ideal targets against filoviral infection and diseases is at the entry step, which is mediated by the filoviral glycoprotein (GP). In this report, we screened a chemical library of small molecules and identified numerous inhibitors, which are known G protein-coupled receptor (GPCR) antagonists targeting different GPCRs, including histamine receptors, 5-HT (serotonin) receptors, muscarinic acetylcholine receptor, and adrenergic receptor. These inhibitors can effectively block replication of both infectious EBOV and MARV, indicating a broad antiviral activity of the GPCR antagonists. The time-of-addition experiment and microscopic studies suggest that GPCR antagonists block filoviral entry at a step following the initial attachment but prior to viral/cell membrane fusion. These results strongly suggest that GPCRs play a critical role in filoviral entry and GPCR antagonists can be developed as an effective anti-EBOV/MARV therapy.IMPORTANCEInfection of Ebola virus and Marburg virus can cause severe illness in humans with a high mortality rate, and currently there is no FDA-approved vaccine or therapeutic treatment available. The 2013-2015 epidemic in West Africa underscores a lack of our understanding in the infection and pathogenesis of these viruses and the urgency of drug discovery and development. In this study, we have identified numerous inhibitors that are known G protein-coupled receptor (GPCR) antagonists targeting different GPCRs. These inhibitors can effectively block replication of both infectious EBOV and MARV, indicating a broad antiviral activity of the GPCR antagonists. Our results strongly suggest that GPCRs play a critical role in filoviral entry and GPCR antagonists can be developed as an effective anti-EBOV/MARV therapy.

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