| 1. |
- Barki-Harrington, Liza, et al.
(författare)
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Requirement for direct cross-talk between B1 and B2 kinin receptors for the proliferation of androgen-insensitive prostate cancer PC3 cells
- 2003
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Ingår i: Biochemical Journal. - 0264-6021. ; 371, s. 581-587
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Tidskriftsartikel (refereegranskat)abstract
- Stimulation of endogenous kinin receptors promotes growth of androgen-independent prostate cancer PC3 cells via activation of the mitogenic extracellular-signal-regulated kinase (ERK) pathway. In the present study, we show that kinin-mediated mitogenic signalling and prostate-cell growth involves two subtypes of bradykinin (BK) receptors, B1R and B2R. Specific stimulation of either B1R or B2R by their respective agonists des-Arg(9)-BK and Lys-BK promoted ERK activation and cell growth, whereas selective blockade with specific antagonists des-Arg(9)-[Leu(8)]BK and Hoe 140 respectively obliterated this effect, indicating the presence of both receptor subtypes. However, blockade of B1R also inhibited B2R-mediated ERK activation and cell growth, and, similarly, antagonism of B2R inhibited the B1R-mediated response. Furthermore, both B1R and B2R agonists promoted internalization of B1R, whereas both receptor antagonists blocked this effect. The B1R ligands des-Arg(9)-BK and des-Arg(9)-[Leu(8)]BK had no effect on the binding of BK to B2R, as demonstrated by radioligand competitive binding studies. However, blockade of either B1R or B2R impaired the ability of the reciprocal receptor to produce inositol phosphates, suggesting that the interaction between B1R and B2R is proximal to activation of phospholipase C. These results provide evidence for the existence of B1R-B2R complexes in prostate cancer PC3 cells and demonstrate that antagonism of one receptor interferes with the signalling ability of the other, possibly at the level of receptor-Galpha(q) protein coupling. Selective inhibition of B1R, which is up-regulated in injured and cancerous tissue, may be beneficial for the treatment of advanced prostate cancer.
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| 2. |
- Bengtson, Sara, et al.
(författare)
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Activation of TAFI on the Surface of Streptococcus pyogenes Evokes Inflammatory Reactions by Modulating the Kallikrein/Kinin System
- 2009
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Ingår i: Journal of Innate Immunity. - : S. Karger AG. - 1662-811X .- 1662-8128. ; 1:1, s. 18-28
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Tidskriftsartikel (refereegranskat)abstract
- Bacteria-controlled regulation of host responses to infection is an important virulence mechanism that has been demonstrated to contribute to disease progression. Here we report that the human pathogen Streptococcus pyogenes employs the procarboxypeptidase TAR (thrombin-activatablefibrinolysis inhibitor) to modulate the kallikrein/kinin system. To this end, bacteria initiate a chain of events starting with the recruitment and activation of TAFI. This is followed by the assembly and induction of the contact system at the streptococcal surface, eventually triggering the release of bradykinin (BK). BK is then carboxyterminally truncated by activated TAFI, which converts the peptide from a kinin B-2 receptor ligand to a kinin B-1 receptor (B1R) agonist. Finally, we show that streptococcal supernatants indirectly amplify the B1R response as they act on peripheral blood mononuclear cells to secrete inflammatory cytokines that in turn stimulate upregulation of the B1R on human fibroblasts. Taken together our findings implicate a critical and novel role for streptococci-bound TAR, as it processes BK to a B1R agonist at the bacterial surface and thereby may redirect inflammation from a transient to a chronic state. Copyright (C) 2008 S. Karger AG, Basel
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| 3. |
- Bengtson, Sara H, et al.
(författare)
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Kinin receptor expression during Staphylococcus aureus infection.
- 2006
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Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 108:6, s. 2055-2063
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Tidskriftsartikel (refereegranskat)abstract
- An inappropriate host response to invading bacteria is a critical parameter that often aggravates the outcome of an infection. Staphylococcus aureus is a major human Gram-positive pathogen that causes a wide array of community- and hospital-acquired diseases ranging from superficial skin infections to severe conditions such as staphylococcal toxic shock. Here we find that S aureus induces inflammatory reactions by modulating the expression and response of the B1 and B2 receptors, respectively. This process is initiated by a chain of events, involving staphylococcal-induced cytokine release from monocytes, bacteria-triggered contact activation, and conversion of bradykinin to its metabolite desArg9bradykinin. The data of the present study implicate an important and previously unknown role for kinin receptor regulation in S aureus infections.
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| 4. |
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| 5. |
- Broselid, Stefan, et al.
(författare)
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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
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 289:32, s. 22117-22127
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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.
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| 6. |
- de Valdivia, Ernesto Gonzalez, et al.
(författare)
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Roles of PDZ-dependent Interactions and N-glycosylation in G Protein-coupled Estrogen Receptor 1 (GPER1)/GPR30-mediated Stimulation of ERK1/2 Activity
- 2018
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Ingår i: FASEB Journal. - : Wiley. - 0892-6638 .- 1530-6860. ; 32:1 Suppl, s. 6-685
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Konferensbidrag (refereegranskat)abstract
- G protein-coupled receptor 30 (GPR30) is a G protein-coupled receptor (GPCR) that is attracting considerable attention in breast cancer and cardiometabolic regulation. Following reports that GPR30 is required for some rapid estrogen responses, e.g. increased cAMP production and ERK1/2 activity, in estrogen receptor (ER)-negative cells, GPR30 was renamed G protein-coupled estrogen receptor 1 (GPER1). However, many questions remain about the identity of the cognate receptor ligand, receptor-effector coupling, and receptor membrane trafficking. To address the mechanism by which human GPR30 activates ERK1/2, we used HEK293 cells with and without ectopic expression of GPR30. Specifically, we investigated the role of the type I PSD-95/Discs-large/ZO-1 homology (PDZ) motif at the receptor C terminus (-SSAV) and three consensus sites for N glycosylation (N-X-S/T) in the receptor N-terminal domain (N25, N32, N44). We found previously that the C-terminal PDZ motif enables the receptor to interact with SAP97 and protein kinase A (PKA)-anchoring protein (AKAP) 5, and this interaction is necessary for retaining the receptor in the plasma membrane and mediating a constitutive decrease in cAMP production that is not inhibited by pertussis toxin, thus independent of Gi/o. Here, we found that the receptor also constitutively increases ERK1/2 activity. Interestingly, this increase was inhibited by PTX as well as by wortmannin, but not by AG1478, indicating it is mediated by Gi/o and phosphoinositide 3-kinase (PI3K) but not epidermal growth factor receptor (EGFR) transactivation. Deleting the receptor PDZ motif or knocking down AKAP5 also inhibited the increase, showing that the PDZ interaction is also necessary for this response. Interestingly, the proposed GPR30 agonist G-1 increased ERK1/2 activity in a GPR30-dependent manner, but this increase was only observed at very low levels of receptor expression below that required for the constitutive increase. Furthermore, deleting the PDZ motif, which completely inhibited the constitutive increase in ERK1/2 activity, did not inhibit the G-1-stimulated increase. Mutating the potential N-glycosylation residues N25 or N32 to I in the GPR30 N-terminal domain did not prevent receptor plasma membrane expression or ERK1/2 activation. On the other hand, mutating N44 to I completely prevented both plasma membrane expression and ERK1/2 activation, and caused receptor degradation. Thus, the PDZ-dependent receptor interaction with SAP97 and AKAP5, and therefore plasma membrane retention, is necessary for constitutive GPR30-mediated stimulation of ERK1/2 activation, whereas G-1-stimulated ERK1/2 activation may remain following constitutive internalization. On the other hand, N-glycosylation of N44 appears to be necessary for maturation of the receptor to the plasma membrane. Support or Funding Information Swedish Research Council and Swedish Cancer Foundation This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
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| 7. |
- Enquist, Johan, et al.
(författare)
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Kinin-Stimulated B1 Receptor Signaling Depends on Receptor Endocytosis Whereas B2 Receptor Signaling Does Not.
- 2014
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Ingår i: Neurochemical Research. - : Springer Science and Business Media LLC. - 1573-6903 .- 0364-3190. ; 39:6, s. 1037-1047
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Tidskriftsartikel (refereegranskat)abstract
- Kinins are potent pro-inflammatory peptides that act through two G protein-coupled receptor subtypes, B1 (B1R) and B2 (B2R). Kinin-stimulated B2R signaling is often transient, whereas B1R signaling is sustained. This was confirmed by monitoring agonist-stimulated intracellular Ca(2+) mobilization in A10 smooth muscle cells expressing human wild-type B2R and B1R. We further studied the role of receptor membrane trafficking in receptor-mediated phosphoinositide (PI) hydrolysis in model HEK293 cell lines stably expressing the receptors. Treatment of cells with brefeldin A, to inhibit maturation of de novo synthesized receptors, or hypertonic sucrose, to inhibit receptor endocytosis, showed that the basal cell surface receptor turnover was considerably faster for B1R than for B2R. Inhibition of endocytosis, which stabilized B1R on the cell surface, inhibited B1R signaling, whereas B2R signaling was not perturbed. Signaling by a B1R construct in which the entire C-terminal domain was deleted remained sensitive to inhibition of receptor endocytosis, whereas signaling by a B1R construct in which this domain was substituted with the corresponding domain in B2R was not sensitive. B2R and B1R co-expression, which also appeared to stabilize B1R on the cell surface, presumably by receptor hetero-dimerization, also inhibited B1R signaling, whereas B2R signaling was slightly enhanced. Furthermore, the B2R-specific agonist bradykinin (BK) directed both receptors through a common endocytic pathway, whereas the B1R-specific agonist Lys-desArg(9)-BK was unable to do so. These results suggest that B1R-mediated PI hydrolysis depends on a step in receptor endocytosis, whereas B2R-mediated PI hydrolysis does not. We propose that B1R uses at least part of the endocytic machinery to sustain agonist-promoted signaling.
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| 8. |
- Enquist, Johan, et al.
(författare)
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Kinins promote B2 receptor endocytosis and delay constitutive B1 receptor endocytosis.
- 2007
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Ingår i: Molecular Pharmacology. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 1521-0111 .- 0026-895X. ; 71:2, s. 494-507
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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.
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| 9. |
- Gonzalez de Valdivia, Ernesto, et al.
(författare)
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Human G protein-coupled Receptor 30 (GPR30) is N -glycosylated and N-terminal Domain Asparagine 44 is Required for Receptor Structure and Activity
- 2019
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Ingår i: Bioscience Reports. - 0144-8463. ; 39:2
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Tidskriftsartikel (refereegranskat)abstract
- 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 HEK293 cells ectopically expressing N-terminally FLAG-tagged human GPR30 and three unique antibodies (Ab) specifically targeting 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 ERK1/2 activity. GPR30 expression was complex with receptor species spanning from about 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 about 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 roles.
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| 10. |
- Gonzalez, Ernesto, et al.
(författare)
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G protein-coupled Estrogen Receptor 1 (GPER1)/GPR30 Increases ERK1/2 Activity Through PDZ-dependent and -independent Mechanisms
- 2017
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; , s. 9932-9943
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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.
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