| 1. |
- 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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| 2. |
- Karlsson, Emma, et al.
(författare)
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The punishment of death : Concerning an archaeological excavation of an execution site in Vadstena (Sweden)
- 2012
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Ingår i: Richtstättenarchäologie 3. - Dormagen : archaeotopos-Buchverlag. - 9783938473177 ; , s. 154-159
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This article consists of three sections and is a summary of a book about an archeological excavation of an execution site in Vadstena, Sweden. In the section "Forgotten Graves at the Gallows Hill" (Emma Karlsson) mainly concernes the archaeological excavations at Vadstena, but also briefly mentions the compilation of fourteen other excavations. The section "To this, Nobody can be indifferent (Caroline Arcini) deals with the osteological analysis. In the third section "Alienation from society and the symbolism of punishment" (Annika Sandén) the lives of people living on the outer reaches of society during the sixteenth and sevenetenth century are illuminated.
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| 3. |
- Sandén, Caroline, et al.
(författare)
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G Protein-Coupled Estrogen Receptor 1 (GPER1)/GPR30 Localizes in the Plasma Membrane and Trafficks Intracellularly on Cytokeratin Intermediate Filaments.
- 2011
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Ingår i: Molecular Pharmacology. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 1521-0111 .- 0026-895X. ; 79:3, s. 400-410
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Tidskriftsartikel (refereegranskat)abstract
- GPR30, or G protein-coupled estrogen receptor 1 (GPER1), was recently introduced as a membrane estrogen receptor and a candidate cancer biomarker and therapeutic target. However, several questions surround the subcellular localization and signaling of this receptor. In native cells, including mouse myoblast C(2)C(12) cells, Madine-Darby canine kidney (MDCK) epithelial cells, and human ductal breast epithelial tumor T47-D cells, G-1, a GPER1 agonist, and 17β-estradiol (E2) stimulated GPER1-dependent cAMP production, a defined plasma membrane (PM) event, and recruitment of β-arrestin2 to the PM. Staining of fixed and live cells showed that GPER1 was localized both in the PM and on intracellular structures. One such intracellular structure was identified as cytokeratin (CK) intermediate filaments, including those composed of CK7 and CK8, but apparently not endoplasmatic reticulum (ER), Golgi, or microtubules. Reciprocal co-immunoprecipitation of GPER1 and CKs confirmed an association of these proteins. Live staining also showed that the PM receptors constitutively internalize apparently to reach CK filaments. Receptor localization was supported using FLAG- and HA-tagged GPER1. We conclude that GPER1-mediated stimulation of cAMP production and β-arrestin2 recruitment occur in the PM. Furthermore, the PM receptors constitutively internalize and localize intracellularly on CK. This is the first observation that a G protein-coupled receptor (GPCR) is capable of associating with intermediate filaments, which may be important for GPER1 regulation in epithelial cells and the relationship of this receptor to cancer.
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| 4. |
- Sandén, Caroline, et al.
(författare)
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Kinin B1 receptor homo-oligomerization is required for receptor trafficking to the cell surface.
- 2013
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Ingår i: International Immunopharmacology. - : Elsevier BV. - 1878-1705 .- 1567-5769. ; 15:1, s. 121-128
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Tidskriftsartikel (refereegranskat)abstract
- The kinin B1 receptor (B1R) is a G protein-coupled receptor with pro-inflammatory activity that is latent in healthy tissues but induced by tissue insult. Here, we investigated if B1R homo-oligomerization is a possible mechanism regulating the presentation of this receptor at the level of maturation and trafficking to the cell surface. To this end, we used HEK293 cells stably expressing N-terminal FLAG and HA epitope-tagged wild-type human B1R and an N-terminal receptor fragment, B1stop135, which terminates at the C-terminal end of the third transmembrane domain and has previously been shown to oligomerize with B1R. Receptors were monitored by immunoblotting and immunoprecipitation, receptor function by agonist binding and agonist-promoted phosphoinositide hydrolysis, and receptor trafficking by confocal immunofluorescence microscopy. When expressed alone, B1R is core N-glycosylated and forms oligomers localized intracellularly and on the cell surface. B1stop135 also exists as core N-glycosylated oligomers but is localized exclusively intracellularly. When co-expressed, B1stop135 prevents specifically B1R homo-oligomerization by forming nonfunctional B1R-B1stop135 hetero-oligomers, retains B1R intracellularly at least in part in the endoplasmatic reticulum (ER), increases calnexin binding to the receptor, and increases receptor degradation. We conclude that B1R homo-oligomerization is necessary for B1R maturation and trafficking to the cell surface. Modulating this mechanism may be a novel therapeutic avenue in inflammatory disease.
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