1.
Broselid, Stefan, et al.
(författare)
G Protein-coupled Receptor 30 (GPR30) Forms a Plasma Membrane Complex With Membrane-associated Guanylate Kinases (MAGUKs) and AKAP5 That Constitutively Inhibits cAMP Production.
2014
Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 289:32, s. 22117-22127
Tidskriftsartikel (refereegranskat) abstract
GPR30, or G protein-coupled estrogen receptor (GPER), is a GPCR reported to bind 17β-estradiol (E2), couple to the G proteins Gs and Gi/o, and mediate non-genomic estrogenic responses. However, controversies exist regarding the receptor pharmacological profile, effector coupling, and subcellular localization. We addressed the role of the type I PSD-95/Discs-large/ZO-1 homology (PDZ) motif at the receptor C-terminus in receptor trafficking and coupling to cAMP production in HEK293 cells and CHO cells ectopically expressing the receptor, and in MDCK cells expressing native receptor. GPR30 was localized both intracellularly and in the plasma membrane and subject to limited basal endocytosis. E2 and G-1, reported GPR30 agonists, neither stimulated nor inhibited cAMP production through GPR30, nor influenced receptor localization. Instead, GPR30 constitutively inhibited cAMP production stimulated by a heterologous agonist independently of Gi/o. Moreover, siRNA knockdown of native GPR30 increased cAMP production. Deletion of the receptor PDZ motif interfered with inhibition of cAMP production and increased basal receptor endocytosis. GPR30 interacted with membrane-associated guanylate kinases (MAGUKs), including SAP97 and PSD-95, and A-kinase anchoring protein (AKAP) 5 in the plasma membrane in a PDZ-dependent manner. Knockdown of AKAP5 or St-Ht31 treatment, to disrupt AKAP interaction with protein kinase A (PKA) RIIβ regulatory subunit, decreased inhibition of cAMP production, and St-Ht31 increased basal receptor endocytosis. Thus, GPR30 forms a plasma membrane complex with a MAGUK and AKAP5, which constitutively attenuates cAMP production in response to heterologous agonists independently of Gi/o and retains receptors in the plasma membrane.
2.
Enquist, Johan, et al.
(författare)
Kinins promote B2 receptor endocytosis and delay constitutive B1 receptor endocytosis.
2007
Ingår i: Molecular Pharmacology. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 1521-0111 .- 0026-895X. ; 71:2, s. 494-507
Tidskriftsartikel (refereegranskat) abstract
Upon sustained insult, kinins are released and many kinin responses, such as inflammatory pain, adapt from a B2 receptor (B2R) type in the acute phase to a B1 receptor (B1R) type in the chronic phase. In this study, we show that kinins modulate receptor endocytosis to rapidly decrease B2R and increase B1R on the cell surface. B2Rs, which require agonist for activity, are stable plasma membrane components without agonist but recruit beta-arrestin 2, internalize in a clathrin-dependent manner, and recycle rapidly upon agonist treatment. In contrast, B1Rs, which are inducible and constitutively active, constitutively internalize without agonist via a clathrin-dependent pathway, do not recruit beta-arrestin 2, bind G protein-coupled receptor sorting protein, and target lysosomes for degradation. Agonist delays B1R endocytosis, thus transiently stabilizing the receptor. Most of the receptor trafficking phenotypes are transplantable from one receptor to the other through exchange of the C-terminal receptor tails, indicating that the tails contain epitopes that are important for the binding of protein partners that participate in the endocytic and postendocytic receptor choices. It is noteworthy that the agonist delay of B1R endocytosis is not transplanted to the B2R via the B1R tail, suggesting that this property of the B1R requires another domain. These events provide a rapid kinin-dependent mechanism for 1) regulating the constitutive B1R activity and 2) shifting the balance of accessible receptors in favor of B1R.
3.
Gonzalez, Ernesto, et al.
(författare)
G protein-coupled Estrogen Receptor 1 (GPER1)/GPR30 Increases ERK1/2 Activity Through PDZ-dependent and -independent Mechanisms
2017
Ingår i: Journal of Biological Chemistry. - 1083-351X. ; , s. 9932-9943
Tidskriftsartikel (refereegranskat) abstract
G protein-coupled receptor 30 (GPR30), also called G protein-coupled estrogen receptor 1 (GPER1), is thought to play important roles in breast cancer and cardiometabolic regulation, but many questions remain about ligand activation, effector coupling, and subcellular localization. We showed recently that GPR30 interacts through the C-terminal type I PDZ motif with SAP97 and protein kinase A (PKA)-anchoring protein (AKAP) 5, which anchor the receptor in the plasma membrane and mediate an apparently constitutive decrease in cAMP production independently of Gi/o. Here, we show that GPR30 also constitutively increases ERK1/2 activity. Removing the receptor PDZ motif or knocking down specifically AKAP5 inhibited the increase, showing that this increase also requires the PDZ interaction. However, the increase was inhibited by pertussis toxin (PTX) as well as by wortmannin, but not by AG1478, indicating that Gi/o and phosphoinositide 3-kinase (PI3K) mediate the increase independently of epidermal growth factor receptor (EGFR) transactivation. FK506 and okadaic acid also inhibited the increase, implying that a protein phosphatase is involved. The proposed GPR30 agonist G-1 also increased ERK1/2 activity, but this increase was only observed at a level of receptor expression below that required for the constitutive increase. Furthermore, deleting the PDZ motif did not inhibit the G-1-stimulated increase. Based on these results, we propose that GPR30 increases ERK1/2 activity via two Gi/o-mediated mechanisms; a PDZ-dependent apparently constitutive mechanism, and a PDZ-independent G-1-stimulated mechanism.
4.
Hofmeister, Marlene Vind, et al.
(författare)
17 beta-Estradiol induces nongenomic effects in renal intercalated cells through G protein-coupled estrogen receptor 1
2012
Ingår i: American Journal of Physiology-Renal Physiology. - : American Physiological Society. - 1522-1466 .- 1931-857X. ; 302:3, s. 358-368
Tidskriftsartikel (refereegranskat) abstract
Hofmeister MV, Damkier HH, Christensen BM, Olde B, Leeb-Lundberg LM, Fenton RA, Praetorius HA, Praetorius J. 17 beta-Estradiol induces nongenomic effects in renal intercalated cells through G protein-coupled estrogen receptor 1. Am J Physiol Renal Physiol 302: F358-F368, 2012. First published October 12, 2011; doi: 10.1152/ajprenal.00343.2011.-Steroid hormones such as 17 beta-estradiol (E2) are known to modulate ion transporter expression in the kidney through classic intracellular receptors. Steroid hormones are also known to cause rapid nongenomic responses in a variety of nonrenal tissues. However, little is known about renal short-term effects of steroid hormones. Here, we studied the acute actions of E2 on intracellular Ca2+ signaling in isolated distal convoluted tubules (DCT2), connecting tubules (CNT), and initial cortical collecting ducts (iCCD) by fluo 4 fluorometry. Physiological concentrations of E2 induced transient increases in intracellular Ca2+ concentration ([Ca2+](i)) in a subpopulation of cells. The [Ca2+](i) increases required extracellular Ca2+ and were inhibited by Gd3+. Strikingly, the classic E2 receptor antagonist ICI 182,780 also increased [Ca2+](i), which is inconsistent with the activation of classic E2 receptors. G proteincoupled estrogen receptor 1 (G.PER1 or GPR30) was detected in microdissected DCT2/CNT/iCCD by RT-PCR. Stimulation with the specific GPER1 agonist G-1 induced similar [Ca2+](i) increases as E2, and in tubules from GPER1 knockout mice, E2, G-1, and ICI 182,780 failed to induce [Ca2+](i) elevations. The intercalated cells showed both E2-induced concanamycin-sensitive H+-ATPase activity by BCECF fluorometry and the E2-mediated [Ca2+](i) increment. We propose that E2 via GPER1 evokes [Ca2+](i) transients and increases H+-ATPase activity in intercalated cells in mouse DCT2/CNT/iCCD.
5.
6.
Kang, Dongsoo, et al.
(författare)
B1 Bradykinin Receptor Homo-oligomers in Receptor Cell Surface Expression and Signaling: Effects of Receptor Fragments.
2005
Ingår i: Molecular Pharmacology. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 1521-0111 .- 0026-895X. ; 67:1, s. 309-318
Tidskriftsartikel (refereegranskat) abstract
The human B1 bradykinin receptor is an inducible and constitutively active G protein-coupled receptor that is involved in the inflammatory and pain responses to injury. Here, we investigated the role of B1 receptor homo-oligomerization in cell surface receptor expression. B1 receptors tagged with either the FLAG or hemagglutinin epitope were monitored immunologically and by radio-ligand binding, biotinylation, and phosphoinositide hydrolysis in human embryonic kidney 293 cells. Selective immunoprecipitation, immunoblotting, and immunoelectron microscopy with epitope-specific antibodies together provided evidence for constitutively formed cell surface receptor homo-oligomers. Truncation of the receptor from the N- and C-terminal ends indicated that the epitope for oligomerization seems to be located between Leu26 on top of transmembrane helix 1 and Val71 at the bottom of helix 2. A receptor construct terminating at Asp134 at the bottom of helix 3, B1stop135, was expressed in the cell. It is interesting that this construct behaved as a dominant-negative mutant by competitively preventing formation of intact B1 receptor homo-oligomers, and redistributing B1 receptors from the cell surface to a common intracellular compartment. In contrast, expression of a construct containing the residues downstream of Asp134, B1del(2-134), was inactive in this regard. Together, these results are consistent with a mechanism where constitutive B1 receptor homooligomerization is required for expression of receptors on the cell surface and subsequent constitutive receptor signaling. This may be a novel mechanism by which the cell regulates the presentation of this constitutively highly active receptor at various stages of injury.
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10.
Leeb-Lundberg, Fredrik, et al.
(författare)
International union of pharmacology. XLV. Classification of the kinin receptor family: from molecular mechanisms to pathophysiological consequences.
2005
Ingår i: Pharmacological Reviews. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0031-6997 .- 1521-0081. ; 57:1, s. 27-77
Forskningsöversikt (refereegranskat) abstract
Kinins are proinflammatory peptides that mediate numerous vascular and pain responses to tissue injury. Two pharmacologically distinct kinin receptor subtypes have been identified and characterized for these peptides, which are named B1 and B2 and belong to the rhodopsin family of G protein-coupled receptors. The B2 receptor mediates the action of bradykinin (BK) and lysyl-bradykinin (Lys-BK), the first set of bioactive kinins formed in response to injury from kininogen precursors through the actions of plasma and tissue kallikreins, whereas the B(1) receptor mediates the action of des-Arg9-BK and Lys-des-Arg9-BK, the second set of bioactive kinins formed through the actions of carboxypeptidases on BK and Lys-BK, respectively. The B2 receptor is ubiquitous and constitutively expressed, whereas the B1 receptor is expressed at a very low level in healthy tissues but induced following injury by various proinflammatory cytokines such as interleukin-1beta. Both receptors act through G alpha(q) to stimulate phospholipase C beta followed by phosphoinositide hydrolysis and intracellular free Ca2+ mobilization and through G alpha(i) to inhibit adenylate cyclase and stimulate the mitogen-activated protein kinase pathways. The use of mice lacking each receptor gene and various specific peptidic and nonpeptidic antagonists have implicated both B1 and B2 receptors as potential therapeutic targets in several pathophysiological events related to inflammation such as pain, sepsis, allergic asthma, rhinitis, and edema, as well as diabetes and cancer. This review is a comprehensive presentation of our current understanding of these receptors in terms of molecular and cell biology, physiology, pharmacology, and involvement in human disease and drug development.
