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Vatter P, Schuhholz J, Koenig C, Pfreimer M, Moepps B. Ligand-dependent serum response factor activation by the human CC chemokine receptors CCR2a and CCR2b is mediated by G proteins of the Gqfamily. J Leukoc Biol 2016; 99:979-91. [DOI: 10.1189/jlb.2ma0815-386r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 01/13/2016] [Indexed: 12/31/2022] Open
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52
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Adderley SP, Zhang XE, Breslin JW. Involvement of the H1 Histamine Receptor, p38 MAP Kinase, Myosin Light Chains Kinase, and Rho/ROCK in Histamine-Induced Endothelial Barrier Dysfunction. Microcirculation 2016; 22:237-48. [PMID: 25582918 DOI: 10.1111/micc.12189] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 01/10/2015] [Indexed: 12/26/2022]
Abstract
OBJECTIVE The mechanisms by which histamine increases microvascular permeability remain poorly understood. We tested the hypothesis that H1 receptor activation disrupts the endothelial barrier and investigated potential downstream signals. METHODS We used confluent EC monolayers, assessing TER as an index of barrier function. HUVEC, HCMEC, and HDMEC were compared. Receptor expression was investigated using Western blotting, IF confocal microscopy and RT-PCR. Receptor function and downstream signaling pathways were tested using pharmacologic antagonists and inhibitors, respectively. RESULTS We identified H1-H4 receptors on all three EC types. H1 antagonists did not affect basal TER but prevented the histamine-induced decrease in TER. Blockade of H2 or H3 attenuated the histamine response only in HDMEC, while inhibition of H4 attenuated the response only in HUVEC. Combined inhibition of both PKC and PI3K caused exaggerated histamine-induced barrier dysfunction in HDMEC, whereas inhibition of p38 MAP kinase attenuated the histamine response in all three EC types. Inhibition of RhoA, ROCK, or MLCK also prevented the histamine-induced decrease in TER in HDMEC. CONCLUSION The data suggest that multiple signaling pathways contribute to histamine-induced endothelial barrier dysfunction via the H1 receptor.
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Affiliation(s)
- Shaquria P Adderley
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
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53
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Ohta S, Sakaguchi S, Kobayashi Y, Mizuno N, Tago K, Itoh H. Agonistic antibodies reveal the function of GPR56 in human glioma U87-MG cells. Biol Pharm Bull 2016; 38:594-600. [PMID: 25832639 DOI: 10.1248/bpb.b14-00752] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
GPR56 is a member of the adhesion G protein-coupled receptor (GPCR) and is highly expressed in parts of tumor cells. The involvement of GPR56 in tumorigenesis has been reported. We generated agonistic monoclonal antibodies against human GPR56 and analyzed the action and signaling pathway of GPR56. The antibodies inhibited cell migration through the Gq and Rho pathway in human glioma U87-MG cells. Co-immunoprecipitation analysis indicated that the interaction between the GPR56 extracellular domain and transmembrane domain was potentiated by agonistic antibodies. These results demonstrated that functional antibodies are invaluable tools for GPCR research and should open a new avenue for therapeutic treatment of tumors.
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Affiliation(s)
- Shigeyuki Ohta
- Department of Biomedical Science, Graduate School of Biological Sciences, Nara Institute of Science and Technolog
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Otsu K, Harada H. Rho GTPases in ameloblast differentiation. JAPANESE DENTAL SCIENCE REVIEW 2015; 52:32-40. [PMID: 28408954 PMCID: PMC5382790 DOI: 10.1016/j.jdsr.2015.09.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 08/04/2015] [Accepted: 09/22/2015] [Indexed: 01/12/2023] Open
Abstract
During tooth development, ameloblasts differentiate from inner enamel epithelial cells to enamel-forming cells by modulating the signal pathways mediating epithelial–mesenchymal interaction and a cell-autonomous gene network. The differentiation process of epithelial cells is characterized by marked changes in their morphology and polarity, accompanied by dynamic cytoskeletal reorganization and changes in cell–cell and cell–matrix adhesion over time. Functional ameloblasts are tall, columnar, polarized cells that synthesize and secrete enamel-specific proteins. After deposition of the full thickness of enamel matrix, ameloblasts become smaller and regulate enamel maturation. Recent significant advances in the fields of molecular biology and genetics have improved our understanding of the regulatory mechanism of the ameloblast cell life cycle, mediated by the Rho family of small GTPases. They act as intracellular molecular switch that transduce signals from extracellular stimuli to the actin cytoskeleton and the nucleus. In our review, we summarize studies that provide current evidence for Rho GTPases and their involvement in ameloblast differentiation. In addition to the Rho GTPases themselves, their downstream effectors and upstream regulators have also been implicated in ameloblast differentiation.
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Affiliation(s)
- Keishi Otsu
- Corresponding author. Tel.: +81 19 651 5111x5881; fax: +81 19 908 8017.
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55
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van Unen J, Reinhard NR, Yin T, Wu YI, Postma M, Gadella TWJ, Goedhart J. Plasma membrane restricted RhoGEF activity is sufficient for RhoA-mediated actin polymerization. Sci Rep 2015; 5:14693. [PMID: 26435194 PMCID: PMC4592971 DOI: 10.1038/srep14693] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Accepted: 09/04/2015] [Indexed: 01/08/2023] Open
Abstract
The small GTPase RhoA is involved in cell morphology and migration. RhoA activity is tightly regulated in time and space and depends on guanine exchange factors (GEFs). However, the kinetics and subcellular localization of GEF activity towards RhoA are poorly defined. To study the mechanism underlying the spatiotemporal control of RhoA activity by GEFs, we performed single cell imaging with an improved FRET sensor reporting on the nucleotide loading state of RhoA. By employing the FRET sensor we show that a plasma membrane located RhoGEF, p63RhoGEF, can rapidly activate RhoA through endogenous GPCRs and that localized RhoA activity at the cell periphery correlates with actin polymerization. Moreover, synthetic recruitment of the catalytic domain derived from p63RhoGEF to the plasma membrane, but not to the Golgi apparatus, is sufficient to activate RhoA. The synthetic system enables local activation of endogenous RhoA and effectively induces actin polymerization and changes in cellular morphology. Together, our data demonstrate that GEF activity at the plasma membrane is sufficient for actin polymerization via local RhoA signaling.
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Affiliation(s)
- Jakobus van Unen
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, P.O. Box 94215, NL-1090 GE Amsterdam, The Netherlands
| | - Nathalie R Reinhard
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, P.O. Box 94215, NL-1090 GE Amsterdam, The Netherlands
| | - Taofei Yin
- Center for Cell Analysis and Modeling, University of Connecticut Health Center, 400 Farmington Avenue, Farmington, CT 06032-6406
| | - Yi I Wu
- Center for Cell Analysis and Modeling, University of Connecticut Health Center, 400 Farmington Avenue, Farmington, CT 06032-6406
| | - Marten Postma
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, P.O. Box 94215, NL-1090 GE Amsterdam, The Netherlands
| | - Theodorus W J Gadella
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, P.O. Box 94215, NL-1090 GE Amsterdam, The Netherlands
| | - Joachim Goedhart
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, P.O. Box 94215, NL-1090 GE Amsterdam, The Netherlands
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56
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p63RhoGEF regulates auto- and paracrine signaling in cardiac fibroblasts. J Mol Cell Cardiol 2015; 88:39-54. [PMID: 26392029 DOI: 10.1016/j.yjmcc.2015.09.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 09/04/2015] [Accepted: 09/16/2015] [Indexed: 01/14/2023]
Abstract
Cardiac remodeling, a hallmark of heart disease, is associated with intense auto- and paracrine signaling leading to cardiac fibrosis. We hypothesized that the specific mediator of Gq/11-dependent RhoA activation p63RhoGEF, which is expressed in cardiac fibroblasts, plays a role in the underlying processes. We could show that p63RhoGEF is up-regulated in mouse hearts subjected to transverse aortic constriction (TAC). In an engineered heart muscle model (EHM), p63RhoGEF expression in cardiac fibroblasts increased resting and twitch tensions, and the dominant negative p63ΔN decreased both. In an engineered connective tissue model (ECT), p63RhoGEF increased tissue stiffness and its knockdown as well as p63ΔN reduced stiffness. In 2D cultures of neonatal rat cardiac fibroblasts, p63RhoGEF regulated the angiotensin II (Ang II)-dependent RhoA activation, the activation of the serum response factor, and the expression and secretion of the connective tissue growth factor (CTGF). All these processes were inhibited by the knockdown of p63RhoGEF or by p63ΔN likely based on their negative influence on the actin cytoskeleton. Moreover, we show that p63RhoGEF also regulates CTGF in engineered tissues and correlates with it in the TAC model. Finally, confocal studies revealed a closely related localization of p63RhoGEF and CTGF in the trans-Golgi network.
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Masià-Balagué M, Izquierdo I, Garrido G, Cordomí A, Pérez-Benito L, Miller NLG, Schlaepfer DD, Gigoux V, Aragay AM. Gastrin-stimulated Gα13 Activation of Rgnef Protein (ArhGEF28) in DLD-1 Colon Carcinoma Cells. J Biol Chem 2015; 290:15197-209. [PMID: 25922072 PMCID: PMC4463461 DOI: 10.1074/jbc.m114.628164] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Revised: 04/27/2015] [Indexed: 12/15/2022] Open
Abstract
The guanine nucleotide exchange factor Rgnef (also known as ArhGEF28 or p190RhoGEF) promotes colon carcinoma cell motility and tumor progression via interaction with focal adhesion kinase (FAK). Mechanisms of Rgnef activation downstream of integrin or G protein-coupled receptors remain undefined. In the absence of a recognized G protein signaling homology domain in Rgnef, no proximal linkage to G proteins was known. Utilizing multiple methods, we have identified Rgnef as a new effector for Gα13 downstream of gastrin and the type 2 cholecystokinin receptor. In DLD-1 colon carcinoma cells depleted of Gα13, gastrin-induced FAK Tyr(P)-397 and paxillin Tyr(P)-31 phosphorylation were reduced. RhoA GTP binding and promoter activity were increased by Rgnef in combination with active Gα13. Rgnef co-immunoprecipitated with activated Gα13Q226L but not Gα12Q229L. The Rgnef C-terminal (CT, 1279-1582) region was sufficient for co-immunoprecipitation, and Rgnef-CT exogenous expression prevented Gα13-stimulated SRE activity. A domain at the C terminus of the protein close to the FAK binding domain is necessary to bind to Gα13. Point mutations of Rgnef-CT residues disrupt association with active Gα13 but not Gαq. These results show that Rgnef functions as an effector of Gα13 signaling and that this linkage may mediate FAK activation in DLD-1 colon carcinoma cells.
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Affiliation(s)
- Miriam Masià-Balagué
- From the Molecular Biology Institute of Barcelona, Spanish National Research Council (CSIC), 08028 Barcelona, Spain
| | - Ismael Izquierdo
- From the Molecular Biology Institute of Barcelona, Spanish National Research Council (CSIC), 08028 Barcelona, Spain
| | - Georgina Garrido
- From the Molecular Biology Institute of Barcelona, Spanish National Research Council (CSIC), 08028 Barcelona, Spain
| | - Arnau Cordomí
- the Departament de Pediatria, Unitat de Bioestadística, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Laura Pérez-Benito
- the Departament de Pediatria, Unitat de Bioestadística, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Nichol L G Miller
- the Université Paul Sabatier Réceptologie et Ciblage Thérapeutique en Cancérologie, INSERM, Toulouse, France, and
| | - David D Schlaepfer
- the Université Paul Sabatier Réceptologie et Ciblage Thérapeutique en Cancérologie, INSERM, Toulouse, France, and
| | - Véronique Gigoux
- the Moores Cancer Center, University of California at San Diego, La Jolla, California 92093
| | - Anna M Aragay
- From the Molecular Biology Institute of Barcelona, Spanish National Research Council (CSIC), 08028 Barcelona, Spain,
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58
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Kalwa H, Storch U, Demleitner J, Fiedler S, Mayer T, Kannler M, Fahlbusch M, Barth H, Smrcka A, Hildebrandt F, Gudermann T, Dietrich A. Phospholipase C epsilon (PLCε) induced TRPC6 activation: a common but redundant mechanism in primary podocytes. J Cell Physiol 2015; 230:1389-99. [PMID: 25521631 DOI: 10.1002/jcp.24883] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 12/03/2014] [Indexed: 12/22/2022]
Abstract
In eukaryotic cells, activation of phospholipase C (PLC)-coupled membrane receptors by hormones leads to an increase in the intracellular Ca(2+) concentration [Ca(2+) ]i . Catalytic activity of PLCs results in the hydrolysis of phosphatidylinositol 4,5-bisphosphate to generate inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG) which opens DAG-sensitive classical transient receptor channels 3, 6, and 7 (TRPC3/6/7), initiating Ca(2+) influx from the extracellular space. Patients with focal segmental glomerulosclerosis (FSGS) express gain-of-function mutants of TRPC6, while others carry loss-of-function mutants of PLCε, raising the intriguing possibility that both proteins interact and might work in the same signalling pathway. While TRPC6 activation by PLCβ and PLCγ isozymes was extensively studied, the role of PLCε in TRPC6 activation remains elusive. TRPC6 was co-immunoprecipitated with PLCε in a heterologous overexpression system in HEK293 cells as well as in freshly isolated murine podocytes. Receptor-operated TRPC6 currents in HEK293 cells expressing TRPC6 were reduced by a specific PLCε siRNA and by a PLCε loss-of-function mutant isolated from a patient with FSGS. PLCε-induced TRPC6 activation was also identified in murine embryonic fibroblasts (MEFs) lacking Gαq/11 proteins. Further analysis of the signal transduction pathway revealed a Gα12/13 Rho-GEF activation which induced Rho-mediated PLCε stimulation. Therefore, we identified a new pathway for TRPC6 activation by PLCε. PLCε-/- podocytes however, were undistinguishable from WT podocytes in their angiotensin II-induced formation of actin stress fibers and their GTPγS-induced TRPC6 activation, pointing to a redundant role of PLCε-mediated TRPC6 activation at least in podocytes.
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Affiliation(s)
- Hermann Kalwa
- Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
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59
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Zindel D, Butcher AJ, Al-Sabah S, Lanzerstorfer P, Weghuber J, Tobin AB, Bünemann M, Krasel C. Engineered hyperphosphorylation of the β2-adrenoceptor prolongs arrestin-3 binding and induces arrestin internalization. Mol Pharmacol 2014; 87:349-62. [PMID: 25425623 DOI: 10.1124/mol.114.095422] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
G protein-coupled receptor phosphorylation plays a major role in receptor desensitization and arrestin binding. It is, however, unclear how distinct receptor phosphorylation patterns may influence arrestin binding and subsequent trafficking. Here we engineer phosphorylation sites into the C-terminal tail of the β2-adrenoceptor (β2AR) and demonstrate that this mutant, termed β2AR(SSS), showed increased isoprenaline-stimulated phosphorylation and differences in arrestin-3 affinity and trafficking. By measuring arrestin-3 recruitment and the stability of arrestin-3 receptor complexes in real time using fluorescence resonance energy transfer and fluorescence recovery after photobleaching, we demonstrate that arrestin-3 dissociated quickly and almost completely from the β2AR, whereas the interaction with β2AR(SSS) was 2- to 4-fold prolonged. In contrast, arrestin-3 interaction with a β2-adrenoceptor fused to the carboxyl-terminal tail of the vasopressin type 2 receptor was nearly irreversible. Further analysis of arrestin-3 localization revealed that by engineering phosphorylation sites into the β2-adrenoceptor the receptor showed prolonged interaction with arrestin-3 and colocalization with arrestin in endosomes after internalization. This is in contrast to the wild-type receptor that interacts transiently with arrestin-3 at the plasma membrane. Furthermore, β2AR(SSS) internalized more efficiently than the wild-type receptor, whereas recycling was very similar for both receptors. Thus, we show how the interaction between arrestins and receptors can be increased with minimal receptor modification and that relatively modest increases in receptor-arrestin affinity are sufficient to alter arrestin trafficking.
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Affiliation(s)
- Diana Zindel
- Institut für Pharmakologie und Klinische Pharmazie, Philipps-Universität Marburg, Marburg, Germany (D.Z., M.B., C.K.); MRC Toxicology Unit, University of Leicester, Leicester, United Kingdom (A.J.B., A.B.T.); Department of Pharmacology and Toxicology, Kuwait University, Kuwait (S.A.-S.); and University of Applied Sciences Upper Austria, Wels, Austria (P.L., J.W.)
| | - Adrian J Butcher
- Institut für Pharmakologie und Klinische Pharmazie, Philipps-Universität Marburg, Marburg, Germany (D.Z., M.B., C.K.); MRC Toxicology Unit, University of Leicester, Leicester, United Kingdom (A.J.B., A.B.T.); Department of Pharmacology and Toxicology, Kuwait University, Kuwait (S.A.-S.); and University of Applied Sciences Upper Austria, Wels, Austria (P.L., J.W.)
| | - Suleiman Al-Sabah
- Institut für Pharmakologie und Klinische Pharmazie, Philipps-Universität Marburg, Marburg, Germany (D.Z., M.B., C.K.); MRC Toxicology Unit, University of Leicester, Leicester, United Kingdom (A.J.B., A.B.T.); Department of Pharmacology and Toxicology, Kuwait University, Kuwait (S.A.-S.); and University of Applied Sciences Upper Austria, Wels, Austria (P.L., J.W.)
| | - Peter Lanzerstorfer
- Institut für Pharmakologie und Klinische Pharmazie, Philipps-Universität Marburg, Marburg, Germany (D.Z., M.B., C.K.); MRC Toxicology Unit, University of Leicester, Leicester, United Kingdom (A.J.B., A.B.T.); Department of Pharmacology and Toxicology, Kuwait University, Kuwait (S.A.-S.); and University of Applied Sciences Upper Austria, Wels, Austria (P.L., J.W.)
| | - Julian Weghuber
- Institut für Pharmakologie und Klinische Pharmazie, Philipps-Universität Marburg, Marburg, Germany (D.Z., M.B., C.K.); MRC Toxicology Unit, University of Leicester, Leicester, United Kingdom (A.J.B., A.B.T.); Department of Pharmacology and Toxicology, Kuwait University, Kuwait (S.A.-S.); and University of Applied Sciences Upper Austria, Wels, Austria (P.L., J.W.)
| | - Andrew B Tobin
- Institut für Pharmakologie und Klinische Pharmazie, Philipps-Universität Marburg, Marburg, Germany (D.Z., M.B., C.K.); MRC Toxicology Unit, University of Leicester, Leicester, United Kingdom (A.J.B., A.B.T.); Department of Pharmacology and Toxicology, Kuwait University, Kuwait (S.A.-S.); and University of Applied Sciences Upper Austria, Wels, Austria (P.L., J.W.)
| | - Moritz Bünemann
- Institut für Pharmakologie und Klinische Pharmazie, Philipps-Universität Marburg, Marburg, Germany (D.Z., M.B., C.K.); MRC Toxicology Unit, University of Leicester, Leicester, United Kingdom (A.J.B., A.B.T.); Department of Pharmacology and Toxicology, Kuwait University, Kuwait (S.A.-S.); and University of Applied Sciences Upper Austria, Wels, Austria (P.L., J.W.)
| | - Cornelius Krasel
- Institut für Pharmakologie und Klinische Pharmazie, Philipps-Universität Marburg, Marburg, Germany (D.Z., M.B., C.K.); MRC Toxicology Unit, University of Leicester, Leicester, United Kingdom (A.J.B., A.B.T.); Department of Pharmacology and Toxicology, Kuwait University, Kuwait (S.A.-S.); and University of Applied Sciences Upper Austria, Wels, Austria (P.L., J.W.)
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Goicoechea SM, Awadia S, Garcia-Mata R. I'm coming to GEF you: Regulation of RhoGEFs during cell migration. Cell Adh Migr 2014; 8:535-49. [PMID: 25482524 PMCID: PMC4594598 DOI: 10.4161/cam.28721] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cell migration is a highly regulated multistep process that requires the coordinated regulation of cell adhesion, protrusion, and contraction. These processes require numerous protein–protein interactions and the activation of specific signaling pathways. The Rho family of GTPases plays a key role in virtually every aspect of the cell migration cycle. The activation of Rho GTPases is mediated by a large and diverse family of proteins; the guanine nucleotide exchange factors (RhoGEFs). GEFs work immediately upstream of Rho proteins to provide a direct link between Rho activation and cell–surface receptors for various cytokines, growth factors, adhesion molecules, and G protein-coupled receptors. The regulated targeting and activation of RhoGEFs is essential to coordinate the migratory process. In this review, we summarize the recent advances in our understanding of the role of RhoGEFs in the regulation of cell migration.
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Key Words
- DH, Dbl-homology
- DHR, DOCK homology region
- DOCK, dedicator of cytokinesis
- ECM, extracellular matrix
- EGF, epidermal growth factor
- FA, focal adhesion
- FN, fibronectin
- GAP, GTPase activating protein
- GDI, guanine nucleotide dissociation inhibitor
- GEF, guanine nucleotide exchange factor
- GPCR, G protein-coupled receptor
- HGF, hepatocyte growth factor
- LPA, lysophosphatidic acid
- MII, myosin II
- PA, phosphatidic acid
- PDGF, platelet-derived growth factor
- PH, pleckstrin-homology
- PIP2, phosphatidylinositol 4, 5-bisphosphate
- PIP3, phosphatidylinositol (3, 4, 5)-trisphosphate.
- Rho GEFs
- Rho GTPases
- bFGF, basic fibroblast growth factor
- cell migration
- cell polarization
- focal adhesions
- guanine nucleotide exchange factors
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Affiliation(s)
- Silvia M Goicoechea
- a Department of Biological Sciences ; University of Toledo ; Toledo , OH USA
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61
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Meiri D, Marshall CB, Mokady D, LaRose J, Mullin M, Gingras AC, Ikura M, Rottapel R. Mechanistic insight into GPCR-mediated activation of the microtubule-associated RhoA exchange factor GEF-H1. Nat Commun 2014; 5:4857. [PMID: 25209408 DOI: 10.1038/ncomms5857] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 07/31/2014] [Indexed: 12/15/2022] Open
Abstract
The RhoGEF GEF-H1 can be sequestered in an inactive state on polymerized microtubules by the dynein motor light-chain Tctex-1. Phosphorylation of GEF-H1 Ser885 by PKA or PAK kinases creates an inhibitory 14-3-3-binding site. Here we show a new mode of GEF-H1 activation in response to the G-protein-coupled receptor (GPCR) ligands lysophosphatidic acid (LPA) or thrombin that is independent of microtubule depolymerization. LPA/thrombin stimulates disassembly of the GEF-H1:dynein multi-protein complex through the concerted action of Gα and Gβγ. Gα binds directly to GEF-H1 and displaces it from Tctex-1, while Gβγ binds to Tctex-1 and disrupts its interaction with the dynein intermediate chain, resulting in the release of GEF-H1. Full activation of GEF-H1 requires dephosphorylation of Ser885 by PP2A, which is induced by thrombin. The coordinated displacement of GEF-H1 from microtubules by G-proteins and its dephosphorylation by PP2A demonstrate a multistep GEF-H1 activation and present a unique mechanism coupling GPCR signalling to Rho activation.
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Affiliation(s)
- David Meiri
- Department of Biology, Technion Israel Institute of Technology, Haifa 32000, Israel
| | - Christopher B Marshall
- Princess Margaret Cancer Centre, University Health Network, University of Toronto, 101 College Street, Room 12-704, Toronto Medical Discovery Tower, Toronto, Ontario, Canada M5G 1L7
| | - Daphna Mokady
- Princess Margaret Cancer Centre, University Health Network, University of Toronto, 101 College Street, Room 12-704, Toronto Medical Discovery Tower, Toronto, Ontario, Canada M5G 1L7
| | - Jose LaRose
- Princess Margaret Cancer Centre, University Health Network, University of Toronto, 101 College Street, Room 12-704, Toronto Medical Discovery Tower, Toronto, Ontario, Canada M5G 1L7
| | - Michael Mullin
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Room 992A, Toronto, Ontario, Canada M5G 1X5
| | - Anne-Claude Gingras
- 1] Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Room 992A, Toronto, Ontario, Canada M5G 1X5 [2] Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Mitsuhiko Ikura
- 1] Princess Margaret Cancer Centre, University Health Network, University of Toronto, 101 College Street, Room 12-704, Toronto Medical Discovery Tower, Toronto, Ontario, Canada M5G 1L7 [2] Department of Medical Biophysics, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Robert Rottapel
- 1] Princess Margaret Cancer Centre, University Health Network, University of Toronto, 101 College Street, Room 12-704, Toronto Medical Discovery Tower, Toronto, Ontario, Canada M5G 1L7 [2] Department of Medical Biophysics, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8 [3] Department of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8 [4] Department of Immunology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8 [5] Division of Rheumatology, St Michael's Hospital, 30 Bond Street, Toronto, Ontario, Canada M5B 1W8
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Königs V, Jennings R, Vogl T, Horsthemke M, Bachg AC, Xu Y, Grobe K, Brakebusch C, Schwab A, Bähler M, Knaus UG, Hanley PJ. Mouse macrophages completely lacking Rho subfamily GTPases (RhoA, RhoB, and RhoC) have severe lamellipodial retraction defects, but robust chemotactic navigation and altered motility. J Biol Chem 2014; 289:30772-30784. [PMID: 25213860 DOI: 10.1074/jbc.m114.563270] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
RhoA is thought to be essential for coordination of the membrane protrusions and retractions required for immune cell motility and directed migration. Whether the subfamily of Rho (Ras homolog) GTPases (RhoA, RhoB, and RhoC) is actually required for the directed migration of primary cells is difficult to predict. Macrophages isolated from myeloid-restricted RhoA/RhoB (conditional) double knock-out (dKO) mice did not express RhoC and were essentially "pan-Rho"-deficient. Using real-time chemotaxis assays, we found that retraction of the trailing edge was dissociated from the advance of the cell body in dKO cells, which developed extremely elongated tails. Surprisingly, velocity (of the cell body) was increased, whereas chemotactic efficiency was preserved, when compared with WT macrophages. Randomly migrating RhoA/RhoB dKO macrophages exhibited multiple small protrusions and developed large "branches" due to impaired lamellipodial retraction. A mouse model of peritonitis indicated that monocyte/macrophage recruitment was, surprisingly, more rapid in RhoA/RhoB dKO mice than in WT mice. In comparison with dKO cells, the phenotypes of single RhoA- or RhoB-deficient macrophages were mild due to mutual compensation. Furthermore, genetic deletion of RhoB partially reversed the motility defect of macrophages lacking the RhoGAP (Rho GTPase-activating protein) myosin IXb (Myo9b). In conclusion, the Rho subfamily is not required for "front end" functions (motility and chemotaxis), although both RhoA and RhoB are involved in pulling up the "back end" and resorbing lamellipodial membrane protrusions. Macrophages lacking Rho proteins migrate faster in vitro, which, in the case of the peritoneum, translates to more rapid in vivo monocyte/macrophage recruitment.
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Affiliation(s)
- Volker Königs
- Institut für Molekulare Zellbiologie, Wilhelms-Universität Münster, 48149 Münster, Germany
| | | | - Thomas Vogl
- Institut für Immunologie, Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Markus Horsthemke
- Institut für Molekulare Zellbiologie, Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Anne C Bachg
- Institut für Molekulare Zellbiologie, Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Yan Xu
- Institut für Molekulare Zellbiologie, Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Kay Grobe
- Institut für Physiologische Chemie und Pathobiochemie, and Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Cord Brakebusch
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark
| | - Albrecht Schwab
- Institut für Physiologie II, Wilhelms-Universität Münster, 48149 Münster, Germany, and
| | - Martin Bähler
- Institut für Molekulare Zellbiologie, Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Ulla G Knaus
- Conway Institute, University College Dublin, Dublin, Ireland
| | - Peter J Hanley
- Institut für Molekulare Zellbiologie, Wilhelms-Universität Münster, 48149 Münster, Germany,.
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63
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Schmidt S, Debant A. Function and regulation of the Rho guanine nucleotide exchange factor Trio. Small GTPases 2014; 5:e29769. [PMID: 24987837 DOI: 10.4161/sgtp.29769] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Rho GTPases oscillate between an inactive GDP-bound state and an active GTP-bound state. They are activated by Rho Guanine nucleotide Exchange Factors (GEF), which accelerate the GDP to GTP exchange. RhoGEFs fall into two different classes: the Dbl family and the DOCK family of proteins. In this review, we focus on the function and regulation of the Dbl family RhoGEF Trio. Trio and its paralog Kalirin are unique within this family in that they display two GEF domains of distinct specificity. Trio is a major regulator of neuronal development, and its function is conserved through evolution. Moreover, Trio plays an important role in cell adhesion and in signaling pathways elicited by Gαq protein-coupled receptors. Combined, these observations suggest that Trio has a major role in cellular physiology. Of note, Trio is an essential gene for mouse development, with a prominent role in the development of the nervous system. Finally, Trio expression is significantly increased in different types of tumors and it has been proposed that it could participate in oncogenesis.
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Affiliation(s)
- Susanne Schmidt
- Centre de Recherche en Biochimie Macromoléculaire; CNRS - UMR 5237; Université de Montpellier; Montpellier, France
| | - Anne Debant
- Centre de Recherche en Biochimie Macromoléculaire; CNRS - UMR 5237; Université de Montpellier; Montpellier, France
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64
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Gadang V, Konaniah E, Hui DY, Jaeschke A. Mixed-lineage kinase 3 deficiency promotes neointima formation through increased activation of the RhoA pathway in vascular smooth muscle cells. Arterioscler Thromb Vasc Biol 2014; 34:1429-36. [PMID: 24790140 PMCID: PMC4084683 DOI: 10.1161/atvbaha.114.303439] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Mitogen-activated protein kinase pathways play an important role in neointima formation secondary to vascular injury, in part by promoting proliferation of vascular smooth muscle cells (VSMC). Mixed-lineage kinase 3 (MLK3) is a mitogen-activated protein kinase kinase kinase that activates multiple mitogen-activated protein kinase pathways and has been implicated in regulating proliferation in several cell types. However, the role of MLK3 in VSMC proliferation and neointima formation is unknown. The aim of this study was to determine the function of MLK3 in the development of neointimal hyperplasia and to elucidate the underlying mechanisms. APPROACH AND RESULTS Neointima formation was analyzed after endothelial denudation of carotid arteries from wild-type and MLK3-deficient mice. MLK3 deficiency promoted injury-induced neointima formation and increased proliferation of primary VSMC derived from aortas isolated from MLK3-deficient mice compared with wild-type mice. Furthermore, MLK3 deficiency increased the activation of p63Rho guanine nucleotide exchange factor, RhoA, and Rho kinase in VSMC, a pathway known to promote neointimal hyperplasia, and reconstitution of MLK3 expression attenuated Rho kinase activation. Furthermore, cJun NH2-terminal kinase activation was decreased in MLK3-deficient VSMC, and proliferation of wild-type but not MLK3 knockout cells treated with a cJun NH2-terminal kinase inhibitor was attenuated. CONCLUSIONS We demonstrate that MLK3 limits RhoA activation and injury-induced neointima formation by binding to and inhibiting the activation of p63Rho guanine nucleotide exchange factor, a RhoA activator. In MLK3-deficient cells, activation of p63Rho guanine nucleotide exchange factor proceeds in an unchecked manner, leading to a net increase in RhoA pathway activation. Reconstitution of MLK3 expression restores MLK3/p63Rho guanine nucleotide exchange factor interaction, which is attenuated by feedback from activated cJun NH2-terminal kinase.
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MESH Headings
- Animals
- Carotid Arteries/enzymology
- Carotid Arteries/pathology
- Carotid Artery Injuries/enzymology
- Carotid Artery Injuries/genetics
- Carotid Artery Injuries/pathology
- Cell Proliferation
- Cells, Cultured
- Disease Models, Animal
- Hyperplasia
- JNK Mitogen-Activated Protein Kinases/antagonists & inhibitors
- JNK Mitogen-Activated Protein Kinases/metabolism
- MAP Kinase Kinase Kinases/deficiency
- MAP Kinase Kinase Kinases/genetics
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Muscle, Smooth, Vascular/pathology
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/enzymology
- Myocytes, Smooth Muscle/pathology
- Neointima
- Protein Kinase Inhibitors/pharmacology
- Rho Guanine Nucleotide Exchange Factors/metabolism
- Signal Transduction
- Time Factors
- rho GTP-Binding Proteins/metabolism
- rho-Associated Kinases/metabolism
- rhoA GTP-Binding Protein
- Mitogen-Activated Protein Kinase Kinase Kinase 11
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Affiliation(s)
- Vidya Gadang
- From the Department of Pathology, Metabolic Diseases Institute, University of Cincinnati, OH
| | - Eddy Konaniah
- From the Department of Pathology, Metabolic Diseases Institute, University of Cincinnati, OH
| | - David Y Hui
- From the Department of Pathology, Metabolic Diseases Institute, University of Cincinnati, OH
| | - Anja Jaeschke
- From the Department of Pathology, Metabolic Diseases Institute, University of Cincinnati, OH.
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65
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Patel M, Kawano T, Suzuki N, Hamakubo T, Karginov AV, Kozasa T. Gα13/PDZ-RhoGEF/RhoA signaling is essential for gastrin-releasing peptide receptor-mediated colon cancer cell migration. Mol Pharmacol 2014; 86:252-62. [PMID: 24958816 DOI: 10.1124/mol.114.093914] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Gastrin-releasing peptide receptor (GRPR) is ectopically expressed in over 60% of colon cancers. GRPR expression has been correlated with increased colon cancer cell migration. However, the signaling pathway by which GRPR activation leads to increased cancer cell migration is not well understood. We set out to molecularly dissect the GRPR signaling pathways that control colon cancer cell migration through regulation of small GTPase RhoA. Our results show that GRP stimulation activates RhoA predominantly through G13 heterotrimeric G-protein signaling. We also demonstrate that postsynaptic density 95/disk-large/ZO-1 (PDZ)-RhoGEF (PRG), a member of regulator of G-protein signaling (RGS)-homology domain (RH) containing guanine nucleotide exchange factors (RH-RhoGEFs), is the predominant activator of RhoA downstream of GRPR. We found that PRG is required for GRP-stimulated colon cancer cell migration, through activation of RhoA-Rho-associated kinase (ROCK) signaling axis. In addition, PRG-RhoA-ROCK pathway also contributes to cyclo-oxygenase isoform 2 (Cox-2) expression. Increased Cox-2 expression is correlated with increased production of prostaglandin-E2 (PGE2), and Cox-2-PGE2 signaling contributes to total GRPR-mediated cancer cell migration. Our analysis reveals that PRG is overexpressed in colon cancer cell lines. Overall, our results have uncovered a key mechanism for GRPR-regulated colon cancer cell migration through the Gα13-PRG-RhoA-ROCK pathway.
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Affiliation(s)
- Maulik Patel
- Department of Pharmacology, University of Illinois at Chicago College of Medicine, Chicago, Illinois (M.P., A.V.K., T.Ko.); Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia (T. Ka.); and Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan (N.S., T.H., T.Ko.)
| | - Takeharu Kawano
- Department of Pharmacology, University of Illinois at Chicago College of Medicine, Chicago, Illinois (M.P., A.V.K., T.Ko.); Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia (T. Ka.); and Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan (N.S., T.H., T.Ko.)
| | - Nobuchika Suzuki
- Department of Pharmacology, University of Illinois at Chicago College of Medicine, Chicago, Illinois (M.P., A.V.K., T.Ko.); Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia (T. Ka.); and Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan (N.S., T.H., T.Ko.)
| | - Takao Hamakubo
- Department of Pharmacology, University of Illinois at Chicago College of Medicine, Chicago, Illinois (M.P., A.V.K., T.Ko.); Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia (T. Ka.); and Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan (N.S., T.H., T.Ko.)
| | - Andrei V Karginov
- Department of Pharmacology, University of Illinois at Chicago College of Medicine, Chicago, Illinois (M.P., A.V.K., T.Ko.); Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia (T. Ka.); and Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan (N.S., T.H., T.Ko.)
| | - Tohru Kozasa
- Department of Pharmacology, University of Illinois at Chicago College of Medicine, Chicago, Illinois (M.P., A.V.K., T.Ko.); Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia (T. Ka.); and Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan (N.S., T.H., T.Ko.).
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66
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Tsou PS, Haak AJ, Khanna D, Neubig RR. Cellular mechanisms of tissue fibrosis. 8. Current and future drug targets in fibrosis: focus on Rho GTPase-regulated gene transcription. Am J Physiol Cell Physiol 2014; 307:C2-13. [PMID: 24740541 DOI: 10.1152/ajpcell.00060.2014] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Tissue fibrosis occurs with excessive extracellular matrix deposition from myofibroblasts, resulting in tissue scarring and inflammation. It is driven by multiple mediators, such as the G protein-coupled receptor ligands lysophosphatidic acid and endothelin, as well as signaling by transforming growth factor-β, connective tissue growth factor, and integrins. Fibrosis contributes to 45% of deaths in the developed world. As current therapeutic options for tissue fibrosis are limited and organ transplantation is the only effective treatment for end-stage disease, there is an imminent need for efficacious antifibrotic therapies. This review discusses the various molecular pathways involved in fibrosis. It highlights the Rho GTPase signaling pathway and its downstream gene transcription output through myocardin-related transcription factor and serum response factor as a convergence point for targeting this complex set of diseases.
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Affiliation(s)
- Pei-Suen Tsou
- Division of Rheumatology, Department of Internal Medicine, University of Michigan Scleroderma Program, Ann Arbor, Michigan
| | - Andrew J Haak
- Department of Pharmacology, University of Michigan Medical Center, Ann Arbor, Michigan; and
| | - Dinesh Khanna
- Division of Rheumatology, Department of Internal Medicine, University of Michigan Scleroderma Program, Ann Arbor, Michigan
| | - Richard R Neubig
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan
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67
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Dynamics of Gαq-protein-p63RhoGEF interaction and its regulation by RGS2. Biochem J 2014; 458:131-40. [PMID: 24299002 DOI: 10.1042/bj20130782] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Some G-protein-coupled receptors regulate biological processes via Gα12/13- or Gαq/11-mediated stimulation of RhoGEFs (guanine-nucleotide-exchange factors). p63RhoGEF is known to be specifically activated by Gαq/11 and mediates a major part of the acute response of vascular smooth muscle cells to angiotensin II treatment. In order to gain information about the dynamics of receptor-mediated activation of p63RhoGEF, we developed a FRET-based assay to study interactions between Gαq-CFP and Venus-p63RhoGEF in single living cells. Upon activation of histaminergic H1 or muscarinic M3 receptors, a robust FRET signal occurred that allowed for the first time the analysis of the kinetics of this interaction in detail. On- and off-set kinetics of Gαq-p63RhoGEF interactions closely resembled the kinetics of Gαq activity. Analysis of the effect of RGS2 (regulator of G-protein signalling 2) on the dynamics of Gαq activity and their interaction with p63RhoGEF showed that RGS2 is able to accelerate both deactivation of Gαq proteins and dissociation of Gαq and p63RhoGEF to a similar extent. Furthermore, we were able to detect activation-dependent FRET between RGS2 and p63RhoGEF and observed a reduced p63RhoGEF-mediated downstream signalling in the presence of RGS2. In summary, these observations support the concept of a functional activation-dependent p63RhoGEF-Gαq-RGS2 complex.
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68
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Goedhart J, van Unen J, Adjobo-Hermans MJW, Gadella TWJ. Signaling efficiency of Gαq through its effectors p63RhoGEF and GEFT depends on their subcellular location. Sci Rep 2014; 3:2284. [PMID: 23884432 PMCID: PMC3722567 DOI: 10.1038/srep02284] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 07/10/2013] [Indexed: 02/02/2023] Open
Abstract
The p63RhoGEF and GEFT proteins are encoded by the same gene and both members of the Dbl family of guanine nucleotide exchange factors. These proteins can be activated by the heterotrimeric G-protein subunit Gαq. We show that p63RhoGEF is located at the plasma membrane, whereas GEFT is confined to the cytoplasm. Live-cell imaging studies yielded quantitative information on diffusion coefficients, association rates and encounter times of GEFT and p63RhoGEF. Calcium signaling was examined as a measure of the signal transmission, revealing more efficient signaling through the membrane-associated p63RhoGEF. A rapamycin dependent recruitment system was used to dynamically alter the subcellular location and concentration of GEFT, showing efficient signaling through GEFT only upon membrane recruitment. Together, our results show efficient signal transmission through membrane located effectors, and highlight a role for increased concentration rather than increased encounter times due to membrane localization in the Gαq mediated pathways to p63RhoGEF and PLCβ.
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Affiliation(s)
- Joachim Goedhart
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, P.O. Box 94215, NL-1090 GE Amsterdam, The Netherlands.
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69
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Sánchez-Fernández G, Cabezudo S, García-Hoz C, Benincá C, Aragay AM, Mayor F, Ribas C. Gαq signalling: the new and the old. Cell Signal 2014; 26:833-48. [PMID: 24440667 DOI: 10.1016/j.cellsig.2014.01.010] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 01/09/2014] [Indexed: 01/25/2023]
Abstract
In the last few years the interactome of Gαq has expanded considerably, contributing to improve our understanding of the cellular and physiological events controlled by this G alpha subunit. The availability of high-resolution crystal structures has led the identification of an effector-binding region within the surface of Gαq that is able to recognise a variety of effector proteins. Consequently, it has been possible to ascribe different Gαq functions to specific cellular players and to identify important processes that are triggered independently of the canonical activation of phospholipase Cβ (PLCβ), the first identified Gαq effector. Novel effectors include p63RhoGEF, that provides a link between G protein-coupled receptors and RhoA activation, phosphatidylinositol 3-kinase (PI3K), implicated in the regulation of the Akt pathway, or the cold-activated TRPM8 channel, which is directly inhibited upon Gαq binding. Recently, the activation of ERK5 MAPK by Gq-coupled receptors has also been described as a novel PLCβ-independent signalling axis that relies upon the interaction between this G protein and two novel effectors (PKCζ and MEK5). Additionally, the association of Gαq with different regulatory proteins can modulate its effector coupling ability and, therefore, its signalling potential. Regulators include accessory proteins that facilitate effector activation or, alternatively, inhibitory proteins that downregulate effector binding or promote signal termination. Moreover, Gαq is known to interact with several components of the cytoskeleton as well as with important organisers of membrane microdomains, which suggests that efficient signalling complexes might be confined to specific subcellular environments. Overall, the complex interaction network of Gαq underlies an ever-expanding functional diversity that puts forward this G alpha subunit as a major player in the control of physiological functions and in the development of different pathological situations.
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Affiliation(s)
- Guzmán Sánchez-Fernández
- Departamento de Biología Molecular and Centro de Biologia Molecular "Severo Ochoa", CSIC-UAM, Universidad Autónoma de Madrid, Spain; Instituto de Investigación Sanitaria La Princesa, Madrid, Spain
| | - Sofía Cabezudo
- Departamento de Biología Molecular and Centro de Biologia Molecular "Severo Ochoa", CSIC-UAM, Universidad Autónoma de Madrid, Spain; Instituto de Investigación Sanitaria La Princesa, Madrid, Spain
| | - Carlota García-Hoz
- Departamento de Biología Molecular and Centro de Biologia Molecular "Severo Ochoa", CSIC-UAM, Universidad Autónoma de Madrid, Spain; Instituto de Investigación Sanitaria La Princesa, Madrid, Spain
| | | | - Anna M Aragay
- Department of Cell Biology, Molecular Biology Institute of Barcelona, Spain
| | - Federico Mayor
- Departamento de Biología Molecular and Centro de Biologia Molecular "Severo Ochoa", CSIC-UAM, Universidad Autónoma de Madrid, Spain; Instituto de Investigación Sanitaria La Princesa, Madrid, Spain
| | - Catalina Ribas
- Departamento de Biología Molecular and Centro de Biologia Molecular "Severo Ochoa", CSIC-UAM, Universidad Autónoma de Madrid, Spain; Instituto de Investigación Sanitaria La Princesa, Madrid, Spain.
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70
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Lyon AM, Taylor VG, Tesmer JJG. Strike a pose: Gαq complexes at the membrane. Trends Pharmacol Sci 2013; 35:23-30. [PMID: 24287282 DOI: 10.1016/j.tips.2013.10.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 10/16/2013] [Accepted: 10/21/2013] [Indexed: 12/20/2022]
Abstract
The heterotrimeric G protein Gαq is a central player in signal transduction, relaying signals from activated G-protein-coupled receptors (GPCRs) to effectors and other proteins to elicit changes in intracellular Ca(2+), the actin cytoskeleton, and gene transcription. Gαq functions at the intracellular surface of the plasma membrane, as do its best-characterized targets, phospholipase C-β, p63RhoGEF, and GPCR kinase 2 (GRK2). Recent insights into the structure and function of these signaling complexes reveal several recurring themes, including complex multivalent interactions between Gαq, its protein target, and the membrane, that are likely essential for allosteric control and maximum efficiency in signal transduction. Thus, the plasma membrane is not only a source of substrates but also a key player in the scaffolding of Gαq-dependent signaling pathways.
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Affiliation(s)
- Angeline M Lyon
- Life Sciences Institute and the Departments of Pharmacology and Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Veronica G Taylor
- Life Sciences Institute and the Departments of Pharmacology and Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - John J G Tesmer
- Life Sciences Institute and the Departments of Pharmacology and Biological Chemistry, University of Michigan, Ann Arbor, MI, USA.
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71
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George AJ, Purdue BW, Gould CM, Thomas DW, Handoko Y, Qian H, Quaife-Ryan GA, Morgan KA, Simpson KJ, Thomas WG, Hannan RD. A functional siRNA screen identifies genes modulating angiotensin II-mediated EGFR transactivation. J Cell Sci 2013; 126:5377-90. [PMID: 24046455 DOI: 10.1242/jcs.128280] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The angiotensin type 1 receptor (AT1R) transactivates the epidermal growth factor receptor (EGFR) to mediate cellular growth, however, the molecular mechanisms involved have not yet been resolved. To address this, we performed a functional siRNA screen of the human kinome in human mammary epithelial cells that demonstrate a robust AT1R-EGFR transactivation. We identified a suite of genes encoding proteins that both positively and negatively regulate AT1R-EGFR transactivation. Many candidates are components of EGFR signalling networks, whereas others, including TRIO, BMX and CHKA, have not been previously linked to EGFR transactivation. Individual knockdown of TRIO, BMX or CHKA attenuated tyrosine phosphorylation of the EGFR by angiotensin II stimulation, but this did not occur following direct stimulation of the EGFR with EGF, indicating that these proteins function between the activated AT1R and the EGFR. Further investigation of TRIO and CHKA revealed that their activity is likely to be required for AT1R-EGFR transactivation. CHKA also mediated EGFR transactivation in response to another G protein-coupled receptor (GPCR) ligand, thrombin, indicating a pervasive role for CHKA in GPCR-EGFR crosstalk. Our study reveals the power of unbiased, functional genomic screens to identify new signalling mediators important for tissue remodelling in cardiovascular disease and cancer.
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Affiliation(s)
- Amee J George
- School of Biomedical Sciences, The University of Queensland, St. Lucia, Queensland, 4072, Australia
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72
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Tang X, Jin R, Qu G, Wang X, Li Z, Yuan Z, Zhao C, Siwko S, Shi T, Wang P, Xiao J, Liu M, Luo J. GPR116, an adhesion G-protein-coupled receptor, promotes breast cancer metastasis via the Gαq-p63RhoGEF-Rho GTPase pathway. Cancer Res 2013; 73:6206-18. [PMID: 24008316 DOI: 10.1158/0008-5472.can-13-1049] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Adhesion G-protein-coupled receptors (GPCR), which contain adhesion domains in their extracellular region, have been found to play important roles in cell adhesion, motility, embryonic development, and immune response. Because most adhesion molecules with adhesion domains have vital roles in cancer metastasis, we speculated that adhesion GPCRs are potentially involved in cancer metastasis. In this study, we identified GPR116 as a novel regulator of breast cancer metastasis through expression and functional screening of the adhesion GPCR family. We found that knockdown of GPR116 in highly metastatic (MDA-MB-231) breast cancer cells suppressed cell migration and invasion. Conversely, ectopic GPR116 expression in poorly metastatic (MCF-7 and Hs578T) cells promoted cell invasion. We further showed that knockdown of GPR116 inhibited breast cancer cell metastasis in two mammary tumor metastasis mouse models. Moreover, GPR116 modulated the formation of lamellipodia and actin stress fibers in cells in a RhoA- and Rac1-dependent manner. At a molecular level, GPR116 regulated cell motility and morphology through the Gαq-p63RhoGEF-RhoA/Rac1 pathway. The biologic significance of GPR116 in breast cancer is substantiated in human patient samples, where GPR116 expression is significantly correlated with breast tumor progression, recurrence, and poor prognosis. These findings show that GPR116 is crucial for the metastasis of breast cancer and support GPR116 as a potential prognostic marker and drug target against metastatic human breast cancer.
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Affiliation(s)
- Xiaolong Tang
- Authors' Affiliations: East China Normal University and Shanghai Changzheng Hospital Joint Research Center for Orthopedic Oncology, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China; and Center for Cancer and Stem Cell Biology, Alkek Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas
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73
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Chen W, Oberwinkler H, Werner F, Gaßner B, Nakagawa H, Feil R, Hofmann F, Schlossmann J, Dietrich A, Gudermann T, Nishida M, Del Galdo S, Wieland T, Kuhn M. Atrial Natriuretic Peptide–Mediated Inhibition of Microcirculatory Endothelial Ca
2+
and Permeability Response to Histamine Involves cGMP-Dependent Protein Kinase I and TRPC6 Channels. Arterioscler Thromb Vasc Biol 2013; 33:2121-9. [DOI: 10.1161/atvbaha.113.001974] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Wen Chen
- From the Institute of Physiology, University of Würzburg, Würzburg, Germany (W.C., H.O., F.W., B.G., H.N., M.K.); Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany (R.F.); FOR 923, Technical University München, Garching, Germany (F.H.); Institute of Pharmacology and Toxicology, University of Regensburg, Regensburg, Germany (J.S.); Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University München, Munich, Germany (A.D., T.G.); Department
| | - Heike Oberwinkler
- From the Institute of Physiology, University of Würzburg, Würzburg, Germany (W.C., H.O., F.W., B.G., H.N., M.K.); Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany (R.F.); FOR 923, Technical University München, Garching, Germany (F.H.); Institute of Pharmacology and Toxicology, University of Regensburg, Regensburg, Germany (J.S.); Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University München, Munich, Germany (A.D., T.G.); Department
| | - Franziska Werner
- From the Institute of Physiology, University of Würzburg, Würzburg, Germany (W.C., H.O., F.W., B.G., H.N., M.K.); Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany (R.F.); FOR 923, Technical University München, Garching, Germany (F.H.); Institute of Pharmacology and Toxicology, University of Regensburg, Regensburg, Germany (J.S.); Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University München, Munich, Germany (A.D., T.G.); Department
| | - Birgit Gaßner
- From the Institute of Physiology, University of Würzburg, Würzburg, Germany (W.C., H.O., F.W., B.G., H.N., M.K.); Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany (R.F.); FOR 923, Technical University München, Garching, Germany (F.H.); Institute of Pharmacology and Toxicology, University of Regensburg, Regensburg, Germany (J.S.); Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University München, Munich, Germany (A.D., T.G.); Department
| | - Hitoshi Nakagawa
- From the Institute of Physiology, University of Würzburg, Würzburg, Germany (W.C., H.O., F.W., B.G., H.N., M.K.); Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany (R.F.); FOR 923, Technical University München, Garching, Germany (F.H.); Institute of Pharmacology and Toxicology, University of Regensburg, Regensburg, Germany (J.S.); Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University München, Munich, Germany (A.D., T.G.); Department
| | - Robert Feil
- From the Institute of Physiology, University of Würzburg, Würzburg, Germany (W.C., H.O., F.W., B.G., H.N., M.K.); Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany (R.F.); FOR 923, Technical University München, Garching, Germany (F.H.); Institute of Pharmacology and Toxicology, University of Regensburg, Regensburg, Germany (J.S.); Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University München, Munich, Germany (A.D., T.G.); Department
| | - Franz Hofmann
- From the Institute of Physiology, University of Würzburg, Würzburg, Germany (W.C., H.O., F.W., B.G., H.N., M.K.); Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany (R.F.); FOR 923, Technical University München, Garching, Germany (F.H.); Institute of Pharmacology and Toxicology, University of Regensburg, Regensburg, Germany (J.S.); Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University München, Munich, Germany (A.D., T.G.); Department
| | - Jens Schlossmann
- From the Institute of Physiology, University of Würzburg, Würzburg, Germany (W.C., H.O., F.W., B.G., H.N., M.K.); Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany (R.F.); FOR 923, Technical University München, Garching, Germany (F.H.); Institute of Pharmacology and Toxicology, University of Regensburg, Regensburg, Germany (J.S.); Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University München, Munich, Germany (A.D., T.G.); Department
| | - Alexander Dietrich
- From the Institute of Physiology, University of Würzburg, Würzburg, Germany (W.C., H.O., F.W., B.G., H.N., M.K.); Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany (R.F.); FOR 923, Technical University München, Garching, Germany (F.H.); Institute of Pharmacology and Toxicology, University of Regensburg, Regensburg, Germany (J.S.); Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University München, Munich, Germany (A.D., T.G.); Department
| | - Thomas Gudermann
- From the Institute of Physiology, University of Würzburg, Würzburg, Germany (W.C., H.O., F.W., B.G., H.N., M.K.); Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany (R.F.); FOR 923, Technical University München, Garching, Germany (F.H.); Institute of Pharmacology and Toxicology, University of Regensburg, Regensburg, Germany (J.S.); Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University München, Munich, Germany (A.D., T.G.); Department
| | - Motohiro Nishida
- From the Institute of Physiology, University of Würzburg, Würzburg, Germany (W.C., H.O., F.W., B.G., H.N., M.K.); Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany (R.F.); FOR 923, Technical University München, Garching, Germany (F.H.); Institute of Pharmacology and Toxicology, University of Regensburg, Regensburg, Germany (J.S.); Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University München, Munich, Germany (A.D., T.G.); Department
| | - Sabrina Del Galdo
- From the Institute of Physiology, University of Würzburg, Würzburg, Germany (W.C., H.O., F.W., B.G., H.N., M.K.); Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany (R.F.); FOR 923, Technical University München, Garching, Germany (F.H.); Institute of Pharmacology and Toxicology, University of Regensburg, Regensburg, Germany (J.S.); Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University München, Munich, Germany (A.D., T.G.); Department
| | - Thomas Wieland
- From the Institute of Physiology, University of Würzburg, Würzburg, Germany (W.C., H.O., F.W., B.G., H.N., M.K.); Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany (R.F.); FOR 923, Technical University München, Garching, Germany (F.H.); Institute of Pharmacology and Toxicology, University of Regensburg, Regensburg, Germany (J.S.); Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University München, Munich, Germany (A.D., T.G.); Department
| | - Michaela Kuhn
- From the Institute of Physiology, University of Würzburg, Würzburg, Germany (W.C., H.O., F.W., B.G., H.N., M.K.); Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany (R.F.); FOR 923, Technical University München, Garching, Germany (F.H.); Institute of Pharmacology and Toxicology, University of Regensburg, Regensburg, Germany (J.S.); Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University München, Munich, Germany (A.D., T.G.); Department
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74
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Abstract
Endogenous nucleotides have widespread actions in the cardiovascular system, but it is only recently that the P2X and P2Y receptor subtypes, at which they act, have been identified and subtype-selective agonists and antagonists developed. These advances have greatly increased our understanding of the physiological and pathophysiological functions of P2X and P2Y receptors, but investigation of the clinical usefulness of selective ligands is at an early stage. Nonetheless, the evidence considered in this review demonstrates clearly that various cardiovascular disorders, including vasospasm, hypertension, congestive heart failure and cardiac damage during ischemic episodes, may be viable targets. With further development of novel, selective agonists and antagonists, our understanding will continue to improve and further therapeutic applications are likely to be discovered.
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75
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Kwan DHT, Yung LY, Ye RD, Wong YH. Activation of Ras-dependent signaling pathways by G(14) -coupled receptors requires the adaptor protein TPR1. J Cell Biochem 2013; 113:3486-97. [PMID: 22711498 DOI: 10.1002/jcb.24225] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Many G(q) -coupled receptors mediate mitogenic signals by stimulating extracellular signal-regulated protein kinases (ERKs) that are typically regulated by the small GTPase Ras. Recent studies have revealed that members of the Gα(q) family may possess the ability to activate Ras/ERK by interacting with the adaptor protein tetratricopeptide repeat 1 (TPR1). Within the Gα(q) family, the highly promiscuous Gα(14) can relay signals from numerous receptors. Here, we examined if Gα(14) interacts with TPR1 to stimulate Ras signaling pathways. Expression of the constitutively active Gα(14) QL mutant in HEK293 cells led to the formation of GTP-bound Ras as well as increased phosphorylations of downstream signaling molecules including ERK and IκB kinase. Stimulation of endogenous G(14) -coupled somatostatin type 2 and α(2) -adrenergic receptors produced similar responses in human hepatocellular HepG2 carcinoma cells. Co-immunoprecipitation assays using HEK293 cells demonstrated a stronger association of TPR1 for Gα(14) QL than Gα(14) , suggesting that TPR1 preferentially binds to the GTP-bound form of Gα(14) . Activated Gα(14) also interacted with the Ras guanine nucleotide exchange factors SOS1 and SOS2. Expression of a dominant negative mutant of TPR1 or siRNA-mediated knockdown of TPR1 effectively abolished the ability of Gα(14) to induce Ras signaling in native HepG2 or transfected HEK293 cells. Although expression of the dominant negative mutant of TPR1 suppressed Gα(14) QL-induced phosphorylations of ERK and IκB kinase, it did not affect Gα(14) QL-induced stimulation of phospholipase Cβ or c-Jun N-terminal kinase. Our results suggest that TPR1 is required for Gα(14) to stimulate Ras-dependent signaling pathways, but not for the propagation of signals along Ras-independent pathways.
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Affiliation(s)
- Dawna H T Kwan
- Division of Life Science and the Biotechnology Research Institute, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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76
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Hayashi A, Hiatari R, Tsuji T, Ohashi K, Mizuno K. p63RhoGEF-mediated formation of a single polarized lamellipodium is required for chemotactic migration in breast carcinoma cells. FEBS Lett 2013; 587:698-705. [PMID: 23380069 DOI: 10.1016/j.febslet.2013.01.043] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 01/09/2013] [Accepted: 01/22/2013] [Indexed: 01/01/2023]
Abstract
Short hairpin RNAs targeting 66 Rho-GEFs were screened for inhibition of chemotaxis. Six Rho-GEFs (p63RhoGEF, Trio, Duet, Net1, Frabin/Fgd4, and AAH33666) were found to be required for the serum-induced chemotactic migration of MDA-MB-231 human breast carcinoma cells. Knockdown of p63RhoGEF suppressed serum-induced RhoA activation and chemotaxis and caused the aberrant formation of multiple lamellipodial protrusions after serum stimulation while control cells formed a single polarized lamellipodium. These results indicate that p63RhoGEF plays a crucial role in serum-induced chemotaxis by limiting lamellipodial protrusion to one direction via RhoA activation.
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Affiliation(s)
- Aya Hayashi
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
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77
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Vaqué JP, Dorsam RT, Feng X, Iglesias-Bartolome R, Forsthoefel DJ, Chen Q, Debant A, Seeger MA, Ksander BR, Teramoto H, Gutkind JS. A genome-wide RNAi screen reveals a Trio-regulated Rho GTPase circuitry transducing mitogenic signals initiated by G protein-coupled receptors. Mol Cell 2012. [PMID: 23177739 DOI: 10.1016/j.molcel.2012.10.018] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Activating mutations in GNAQ and GNA11, encoding members of the Gα(q) family of G protein α subunits, are the driver oncogenes in uveal melanoma, and mutations in Gq-linked G protein-coupled receptors have been identified recently in numerous human malignancies. How Gα(q) and its coupled receptors transduce mitogenic signals is still unclear because of the complexity of signaling events perturbed upon Gq activation. Using a synthetic-biology approach and a genome-wide RNAi screen, we found that a highly conserved guanine nucleotide exchange factor, Trio, is essential for activating Rho- and Rac-regulated signaling pathways acting on JNK and p38, and thereby transducing proliferative signals from Gα(q) to the nucleus independently of phospholipase C-β. Indeed, whereas many biological responses elicited by Gq depend on the transient activation of second-messenger systems, Gq utilizes a hard-wired protein-protein-interaction-based signaling circuitry to achieve the sustained stimulation of proliferative pathways, thereby controlling normal and aberrant cell growth.
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Affiliation(s)
- Jose P Vaqué
- Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892-4340, USA
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78
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Langemeijer EV, Slinger E, de Munnik S, Schreiber A, Maussang D, Vischer H, Verkaar F, Leurs R, Siderius M, Smit MJ. Constitutive β-catenin signaling by the viral chemokine receptor US28. PLoS One 2012; 7:e48935. [PMID: 23145028 PMCID: PMC3493591 DOI: 10.1371/journal.pone.0048935] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 10/02/2012] [Indexed: 01/17/2023] Open
Abstract
Chronic activation of Wnt/ß-catenin signaling is found in a variety of human malignancies including melanoma, colorectal and hepatocellular carcinomas. Interestingly, expression of the HCMV-encoded chemokine receptor US28 in intestinal epithelial cells promotes intestinal neoplasia in transgenic mice, which is associated with increased nuclear accumulation of ß-catenin. In this study we show that this viral receptor constitutively activates ß-catenin and enhances ß-catenin-dependent transcription. Our data illustrate that this viral receptor does not activate ß-catenin via the classical Wnt/Frizzled signaling pathway. Analysis of US28 mediated signaling indicates the involvement of the Rho-Rho kinase (ROCK) pathway in the activation of ß-catenin. Moreover, cells infected with HCMV show significant increases in ß-catenin stabilization and signaling, which is mediated to a large extent by expression of US28. The modulation of the ß-catenin signal transduction pathway by a viral chemokine receptor provides alternative regulation of this pathway, with potential relevance for the development of colon cancer and virus-associated diseases.
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Affiliation(s)
- Ellen V Langemeijer
- Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, VU University Amsterdam, The Netherlands
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79
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Momotani K, Somlyo AV. p63RhoGEF: a new switch for G(q)-mediated activation of smooth muscle. Trends Cardiovasc Med 2012; 22:122-7. [PMID: 22902181 DOI: 10.1016/j.tcm.2012.07.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 07/09/2012] [Accepted: 07/10/2012] [Indexed: 02/07/2023]
Abstract
In normal and diseased vascular smooth muscle (SM), the RhoA pathway, which is activated by multiple agonists through G protein-coupled receptors (GPCRs), plays a central role in regulating basal tone and peripheral resistance. Multiple RhoA GTP exchange factors (GEFs) are expressed in SM, raising the possibility that specific agonists coupled to specific GPCRs may couple to distinct RhoGEFs and provide novel therapeutic targets. This review focuses on the function and mechanisms of activation of p63RhoGEF (Arhgef 25; GEFT) recently identified in SM and its possible role in selective targeting of RhoA-mediated regulation of basal blood pressure through agonists that couple through G(αq/11).
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Affiliation(s)
- Ko Momotani
- University of Virginia, Department of Molecular Physiology and Biological Physics, Charlottesville, VA 22908, USA
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80
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Meurs H, Dekkers BGJ, Maarsingh H, Halayko AJ, Zaagsma J, Gosens R. Muscarinic receptors on airway mesenchymal cells: novel findings for an ancient target. Pulm Pharmacol Ther 2012; 26:145-55. [PMID: 22842340 DOI: 10.1016/j.pupt.2012.07.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 07/15/2012] [Accepted: 07/17/2012] [Indexed: 01/25/2023]
Abstract
Since ancient times, anticholinergics have been used as a bronchodilator therapy for obstructive lung diseases. Targets of these drugs are G-protein-coupled muscarinic M(1), M(2) and M(3) receptors in the airways, which have long been recognized to regulate vagally-induced airway smooth muscle contraction and mucus secretion. However, recent studies have revealed that acetylcholine also exerts pro-inflammatory, pro-proliferative and pro-fibrotic actions in the airways, which may involve muscarinic receptor stimulation on mesenchymal, epithelial and inflammatory cells. Moreover, acetylcholine in the airways may not only be derived from vagal nerves, but also from non-neuronal cells, including epithelial and inflammatory cells. Airway smooth muscle cells seem to play a major role in the effects of acetylcholine on airway function. It has become apparent that these cells are multipotent cells that may reversibly adopt (hyper)contractile, proliferative and synthetic phenotypes, which are all under control of muscarinic receptors and differentially involved in bronchoconstriction, airway remodeling and inflammation. Cholinergic contractile tone is increased by airway inflammation associated with asthma and COPD, resulting from exaggerated acetylcholine release as well as increased expression of contraction related proteins in airway smooth muscle. Moreover, muscarinic receptor stimulation promotes proliferation of airway smooth muscle cells as well as fibroblasts, and regulates cytokine, chemokine and extracellular matrix production by these cells, which may contribute to airway smooth muscle growth, airway fibrosis and inflammation. In line, animal models of chronic allergic asthma and COPD have recently demonstrated that tiotropium may potently inhibit airway inflammation and remodeling. These observations indicate that muscarinic receptors have a much larger role in the pathophysiology of obstructive airway diseases than previously thought, which may have important therapeutic implications.
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Affiliation(s)
- Herman Meurs
- Department of Molecular Pharmacology, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
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81
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Kauffenstein G, Laher I, Matrougui K, Guérineau NC, Henrion D. Emerging role of G protein-coupled receptors in microvascular myogenic tone. Cardiovasc Res 2012; 95:223-32. [PMID: 22637750 DOI: 10.1093/cvr/cvs152] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Blood flow autoregulation results from the ability of resistance arteries to reduce or increase their diameters in response to changes in intravascular pressure. The mechanism by which arteries maintain a constant blood flow to organs over a range of pressures relies on this myogenic response, which defines the intrinsic property of the smooth muscle to contract in response to stretch. The resistance to flow created by myogenic tone (MT) prevents tissue damage and allows the maintenance of a constant perfusion, despite fluctuations in arterial pressure. Interventions targeting MT may provide a more rational therapeutic approach in vascular disorders, such as hypertension, vasospasm, chronic heart failure, or diabetes. Despite its early description by Bayliss in 1902, the cellular and molecular mechanisms underlying MT remain poorly understood. We now appreciate that MT requires a complex mechanotransduction converting a physical stimulus (pressure) into a biological response (change in vessel diameter). Although smooth muscle cell depolarization and a rise in intracellular calcium concentration are recognized as cornerstones of the myogenic response, the role of wall strain-induced formation of vasoactive mediators is less well established. The vascular system expresses a large variety of Class 1 G protein-coupled receptors (GPCR) activated by an eclectic range of chemical entities, including peptides, lipids, nucleotides, and amines. These messengers can function in blood vessels as vasoconstrictors. This review focuses on locally generated GPCR agonists and their proposed contributions to MT. Their interplay with pivotal G(q-11) and G(12-13) protein signalling is also discussed.
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Affiliation(s)
- Gilles Kauffenstein
- Biologie Neurovasculaire et Mitochondriale Intégrée, UMR CNRS 6214 INSERM 1083, Université d'Angers, France
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82
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Emami-Nemini A, Gohla A, Urlaub H, Lohse MJ, Klenk C. The Guanine Nucleotide Exchange Factor Vav2 Is a Negative Regulator of Parathyroid Hormone Receptor/Gq Signaling. Mol Pharmacol 2012; 82:217-25. [DOI: 10.1124/mol.112.078824] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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83
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García-Hoz C, Sánchez-Fernández G, García-Escudero R, Fernández-Velasco M, Palacios-García J, Ruiz-Meana M, Díaz-Meco MT, Leitges M, Moscat J, García-Dorado D, Boscá L, Mayor F, Ribas C. Protein kinase C (PKC)ζ-mediated Gαq stimulation of ERK5 protein pathway in cardiomyocytes and cardiac fibroblasts. J Biol Chem 2012; 287:7792-802. [PMID: 22232556 PMCID: PMC3293562 DOI: 10.1074/jbc.m111.282210] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Gq-coupled G protein-coupled receptors (GPCRs) mediate the actions of a variety of messengers that are key regulators of cardiovascular function. Enhanced Gα(q)-mediated signaling plays an important role in cardiac hypertrophy and in the transition to heart failure. We have recently described that Gα(q) acts as an adaptor protein that facilitates PKCζ-mediated activation of ERK5 in epithelial cells. Because the ERK5 cascade is known to be involved in cardiac hypertrophy, we have investigated the potential relevance of this pathway in cardiovascular Gq-dependent signaling using both cultured cardiac cell types and chronic administration of angiotensin II in mice. We find that PKCζ is required for the activation of the ERK5 pathway by Gq-coupled GPCR in neonatal and adult murine cardiomyocyte cultures and in cardiac fibroblasts. Stimulation of ERK5 by angiotensin II is blocked upon pharmacological inhibition or siRNA-mediated silencing of PKCζ in primary cultures of cardiac cells and in neonatal cardiomyocytes isolated from PKCζ-deficient mice. Moreover, upon chronic challenge with angiotensin II, these mice fail to promote the changes in the ERK5 pathway, in gene expression patterns, and in hypertrophic markers observed in wild-type animals. Taken together, our results show that PKCζ is essential for Gq-dependent ERK5 activation in cardiomyocytes and cardiac fibroblasts and indicate a key cardiac physiological role for the Gα(q)/PKCζ/ERK5 signaling axis.
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Affiliation(s)
- Carlota García-Hoz
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), 28049 Madrid, Universidad Autónoma de Madrid, Spain
- the Instituto de Investigación Sanitaria La Princesa, 28006 Madrid, Spain
| | - Guzmán Sánchez-Fernández
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), 28049 Madrid, Universidad Autónoma de Madrid, Spain
- the Instituto de Investigación Sanitaria La Princesa, 28006 Madrid, Spain
| | - Ramón García-Escudero
- the Molecular Oncology Unit, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, 28040 Madrid, Spain
| | | | - Julia Palacios-García
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), 28049 Madrid, Universidad Autónoma de Madrid, Spain
- the Instituto de Investigación Sanitaria La Princesa, 28006 Madrid, Spain
| | - Marisol Ruiz-Meana
- the Vall d'Hebron University Hospital and Research Institute, Universitat Autonoma de Barcelona, 08035 Barcelona, Spain
| | - Maria Teresa Díaz-Meco
- the Tumor Microenvironment Program, Sanford-Burnham Medical Research Institute, La Jolla, California 92037
| | - Michael Leitges
- The Biotechnology Centre of Oslo, University of Oslo, 0317 Oslo, Norway, and
| | - Jorge Moscat
- the Tumor Microenvironment Program, Sanford-Burnham Medical Research Institute, La Jolla, California 92037
| | - David García-Dorado
- the Vall d'Hebron University Hospital and Research Institute, Universitat Autonoma de Barcelona, 08035 Barcelona, Spain
| | - Lisardo Boscá
- the Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, 28029 Madrid, Spain
| | - Federico Mayor
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), 28049 Madrid, Universidad Autónoma de Madrid, Spain
- the Instituto de Investigación Sanitaria La Princesa, 28006 Madrid, Spain
- To whom correspondence may be addressed: Centro de Biología Molecular “Severo Ochoa,” Universidad Autónoma de Madrid, 28049 Madrid, Spain. Tel.: 34-91-1964626; Fax: 34-91-1964420; E-mail:
| | - Catalina Ribas
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), 28049 Madrid, Universidad Autónoma de Madrid, Spain
- the Instituto de Investigación Sanitaria La Princesa, 28006 Madrid, Spain
- To whom correspondence may be addressed: Centro de Biología Molecular “Severo Ochoa”, Universidad Autónoma de Madrid, 28049 Madrid, Spain. Tel.: 34-91-1964640; Fax: 34-91-1964420; E-mail:
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84
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McCoy KL, Gyoneva S, Vellano CP, Smrcka AV, Traynelis SF, Hepler JR. Protease-activated receptor 1 (PAR1) coupling to G(q/11) but not to G(i/o) or G(12/13) is mediated by discrete amino acids within the receptor second intracellular loop. Cell Signal 2012; 24:1351-60. [PMID: 22306780 DOI: 10.1016/j.cellsig.2012.01.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2011] [Revised: 12/27/2011] [Accepted: 01/19/2012] [Indexed: 12/29/2022]
Abstract
Protease-activated receptor 1 (PAR1) is an unusual GPCR that interacts with multiple G protein subfamilies (G(q/11), G(i/o), and G(12/13)) and their linked signaling pathways to regulate a broad range of pathophysiological processes. However, the molecular mechanisms whereby PAR1 interacts with multiple G proteins are not well understood. Whether PAR1 interacts with various G proteins at the same, different, or overlapping binding sites is not known. Here we investigated the functional and specific binding interactions between PAR1 and representative members of the G(q/11), G(i/o), and G(12/13) subfamilies. We report that G(q/11) physically and functionally interacts with specific amino acids within the second intracellular (i2) loop of PAR1. We identified five amino acids within the PAR1 i2 loop that, when mutated individually, each markedly reduced PAR1 activation of linked inositol phosphate formation in transfected COS-7 cells (functional PAR1-null cells). Among these mutations, only R205A completely abolished direct G(q/11) binding to PAR1 and also PAR1-directed inositol phosphate and calcium mobilization in COS-7 cells and PAR1-/- primary astrocytes. In stark contrast, none of the PAR1 i2 loop mutations disrupted direct PAR1 binding to either G(o) or G(12), or their functional coupling to linked pertussis toxin-sensitive ERK phosphorylation and C3 toxin-sensitive Rho activation, respectively. In astrocytes, our findings suggest that PAR1-directed calcium signaling involves a newly appreciated G(q/11)-PLCε pathway. In summary, we have identified key molecular determinants for PAR1 interactions with G(q/11), and our findings support a model where G(q/11), G(i/o) or G(12/13) each bind to distinct sites within the cytoplasmic regions of PAR1.
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Affiliation(s)
- Kelly L McCoy
- Department of Pharmacology, O. Wayne Rollins Research Center, Emory University School of Medicine, Atlanta, GA 30322, USA
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85
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Orth JHC, Aktories K. Molecular biology of Pasteurella multocida toxin. Curr Top Microbiol Immunol 2012; 361:73-92. [PMID: 22371145 DOI: 10.1007/82_2012_201] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Pasteurella multocida toxin (PMT) is the causative agent of progressive atrophic rhinitis in swine. The 146 kDa single-chain toxin harbours discrete domains important for receptor binding, internalisation and biological activity. The molecular basis of the toxin's activity is the deamidation of a specific glutamine residue in the α-subunit of heterotrimeric G proteins. This results in an inhibition of the inherent GTPase activity leading to a constitutively active phenotype of the G protein. Due to the ability of the toxin to act on various families of heterotrimeric G proteins, a large subset of signal transduction pathways is stimulated.
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Affiliation(s)
- Joachim H C Orth
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität Freiburg, Albertstr. 25, 79104, Freiburg, Germany.
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Abstract
The mitogenic toxin from Pasteurella multocida (PMT) is a member of the dermonecrotic toxin family, which includes toxins from Bordetella, Escherichia coli and Yersinia. Members of the dermonecrotic toxin family modulate G-protein targets in host cells through selective deamidation and/or transglutamination of a critical active site Gln residue in the G-protein target, which results in the activation of intrinsic GTPase activity. Structural and biochemical data point to the uniqueness of PMT among these toxins in its structure and action. Whereas the other dermonecrotic toxins act on small Rho GTPases, PMT acts on the α subunits of heterotrimeric G(q) -, G(i) - and G(12/13) -protein families. To date, experimental evidence supports a model in which PMT potently stimulates various mitogenic and survival pathways through the activation of G(q) and G(12/13) signaling, ultimately leading to cellular proliferation, whilst strongly inhibiting pathways involved in cellular differentiation through the activation of G(i) signaling. The resulting cellular outcomes account for the global physiological effects observed during infection with toxinogenic P. multocida, and hint at potential long-term sequelae that may result from PMT exposure.
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Affiliation(s)
- Brenda A Wilson
- Department of Microbiology and Host-Microbe Systems Theme of the Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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87
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An SW, Cha SK, Yoon J, Chang S, Ross EM, Huang CL. WNK1 promotes PIP₂ synthesis to coordinate growth factor and GPCR-Gq signaling. Curr Biol 2011; 21:1979-87. [PMID: 22119528 DOI: 10.1016/j.cub.2011.11.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 10/04/2011] [Accepted: 11/01/2011] [Indexed: 11/27/2022]
Abstract
BACKGROUND PLC-β signaling is generally thought to be mediated by allosteric activation by G proteins and Ca(2+). Although availability of the phosphatidylinositol-4,5-biphosphate (PIP(2)) substrate is limiting in some cases, its production has not been shown to be independently regulated as a signaling mechanism. WNK1 protein kinase is known to regulate ion homeostasis and cause hypertension when expression is increased by gene mutations. However, its signaling functions remain largely elusive. RESULTS Using diacylglycerol-stimulated TRPC6 and inositol trisphosphate-mediated Ca(2+) transients as cellular biosensors, we show that WNK1 stimulates PLC-β signaling in cells by promoting the synthesis of PIP(2) via stimulation of phosphatidylinositol 4-kinase IIIα. WNK1 kinase activity is not required. Stimulation of PLC-β by WNK1 and by Gα(q) are synergistic; WNK1 activity is essential for regulation of PLC-β signaling by G(q)-coupled receptors, and basal input from G(q) is necessary for WNK1 signaling via PLC-β. WNK1 further amplifies PLC-β signaling when it is phosphorylated by Akt kinase in response to insulin-like growth factor. CONCLUSIONS WNK1 is a novel regulator of PLC-β that acts by controlling substrate availability. WNK1 thereby coordinates signaling between G protein and Akt kinase pathways. Because PIP(2) is itself a signaling molecule, regulation of PIP(2) synthesis by WNK1 also allows the cell to initiate PLC signaling while independently controlling the effects of PIP(2) on other targets. These findings describe a new signaling pathway for Akt-activating growth factors, a mechanism for G protein-growth factor crosstalk, and a means to independently control PLC signaling and PIP(2) availability.
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Affiliation(s)
- Sung-Wan An
- Department of Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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88
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Roscioni SS, Maarsingh H, Elzinga CRS, Schuur J, Menzen M, Halayko AJ, Meurs H, Schmidt M. Epac as a novel effector of airway smooth muscle relaxation. J Cell Mol Med 2011; 15:1551-63. [PMID: 20716113 PMCID: PMC3823199 DOI: 10.1111/j.1582-4934.2010.01150.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Dysfunctional regulation of airway smooth muscle tone is a feature of obstructive airway diseases such as asthma and chronic obstructive pulmonary disease. Airway smooth muscle contraction is directly associated with changes in the phosphorylation of myosin light chain (MLC), which is increased by Rho and decreased by Rac. Although cyclic adenosine monophosphate (cAMP)-elevating agents are believed to relieve bronchoconstriction mainly via activation of protein kinase A (PKA), here we addressed the role of the novel cAMP-mediated exchange protein Epac in the regulation of airway smooth muscle tone. Isometric tension measurements showed that specific activation of Epac led to relaxation of guinea pig tracheal preparations pre-contracted with methacholine, independently of PKA. In airway smooth muscle cells, Epac activation reduced methacholine-induced MLC phosphorylation. Moreover, when Epac was stimulated, we observed a decreased methacholine-induced RhoA activation, measured by both stress fibre formation and pull-down assay whereas the same Epac activation prevented methacholine-induced Rac1 inhibition measured by pull-down assay. Epac-driven inhibition of both methacholine-induced muscle contraction by Toxin B-1470, and MLC phosphorylation by the Rac1-inhibitor NSC23766, were significantly attenuated, confirming the importance of Rac1 in Epac-mediated relaxation. Importantly, human airway smooth muscle tissue also expresses Epac, and Epac activation both relaxed pre-contracted human tracheal preparations and decreased MLC phosphorylation. Collectively, we show that activation of Epac relaxes airway smooth muscle by decreasing MLC phosphorylation by skewing the balance of RhoA/Rac1 activation towards Rac1. Therefore, activation of Epac may have therapeutical potential in the treatment of obstructive airway diseases.
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Affiliation(s)
- Sara S Roscioni
- Department of Molecular Pharmacology, University of Groningen, Antonius Deusinglaan 1, Groningen, The Netherlands.
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89
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Harden TK, Waldo GL, Hicks SN, Sondek J. Mechanism of activation and inactivation of Gq/phospholipase C-β signaling nodes. Chem Rev 2011; 111:6120-9. [PMID: 21988240 PMCID: PMC3626114 DOI: 10.1021/cr200209p] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- T Kendall Harden
- Department of Pharmacology and the Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA.
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90
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Momotani K, Artamonov MV, Utepbergenov D, Derewenda U, Derewenda ZS, Somlyo AV. p63RhoGEF couples Gα(q/11)-mediated signaling to Ca2+ sensitization of vascular smooth muscle contractility. Circ Res 2011; 109:993-1002. [PMID: 21885830 DOI: 10.1161/circresaha.111.248898] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
RATIONALE In normal and diseased vascular smooth muscle (SM), the RhoA pathway, which is activated by multiple agonists through G protein-coupled receptors (GPCRs), plays a central role in regulating basal tone and peripheral resistance. This occurs through inhibition of myosin light chain phosphatase, leading to increased phosphorylation of the myosin regulatory light chain. Although it is thought that specific agonists and GPCRs may couple to distinct RhoA guanine nucleotide exchange factors (GEFs), thus raising the possibility of selective targeting of specific GEFs for therapeutic use, this notion is largely unexplored for SM contraction. OBJECTIVE We examine whether p63RhoGEF, known to couple specifically to Gα(q/11) in vitro, is functional in blood vessels as a mediator of RhoA activation and if it is selectively activated by Gα(q/11) coupled agonists. METHODS AND RESULTS We find that p63RhoGEF is present across SM tissues and demonstrate that silencing of the endogenous p63RhoGEF in mouse portal vein inhibits contractile force induced by endothelin-1 to a greater extent than the predominantly Gα(12/13)-mediated thromboxane analog U46619. This is because endothelin-1 acts on Gα(q/11) as well as Gα(12/13). Introduction of the exogenous isolated pleckstrin-homology (PH) domain of p63RhoGEF (residues 331-580) into permeabilized rabbit portal vein inhibited Ca2+ sensitized force and activation of RhoA, when phenylephrine was used as an agonist. This reinforces the results based on endothelin-1, because phenylephrine is thought to act exclusively through Gα(q/11). CONCLUSION We demonstrate that p63RhoGEF selectively couples Gα(q/11) but not Gα(12/13), to RhoA activation in blood vessels and cultured cells and thus mediates the physiologically important Ca2+ sensitization of force induced with Gα(q/11)-coupled agonists. Our results suggest that signaling through p63RhoGEF provides a novel mechanism for selective regulation of blood pressure.
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Affiliation(s)
- Ko Momotani
- University of Virginia, Charlottesville, VA 22908-0736, USA
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91
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Cho SG, Wang Y, Rodriguez M, Tan K, Zhang W, Luo J, Li D, Liu M. Haploinsufficiency in the prometastasis Kiss1 receptor Gpr54 delays breast tumor initiation, progression, and lung metastasis. Cancer Res 2011; 71:6535-46. [PMID: 21852382 DOI: 10.1158/0008-5472.can-11-0329] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Activation of KISS1 receptor (KISS1R or GPR54) by its ligands (Kisspeptins) regulates a diverse function both in normal physiology and pathophysiology. In cancer, KISS1R has been implicated in tumor angiogenesis and metastasis, but a broader evaluation of KISS1R in tumorigenesis and tumor progression is yet to be conducted. In this study, we used mouse models of Kiss1r gene knockout and mouse mammary tumor virus-polyoma virus middle T antigen (MMTV-PyMT)-induced breast cancer to conduct such an evaluation. Kiss1r heterozygosity in MMTV-PyMT mice was sufficient to attenuate breast cancer initiation, growth, latency, multiplicity, and lung metastasis. To confirm these effects and assess possible contributions of endogenous ligands, we isolated primary tumor cells from PyMT/Kiss1r(+/+) and PyMT/Kiss1r(+/-) mice and compared their phenotypes by in vitro and in vivo assays. Kiss1r loss attenuated in vitro tumorigenic properties as well as tumor growth in vivo in immunocompromised NOD.SCID/NCr mice. Kiss1r activation in these cells, resulting from the addition of its ligand Kisspeptin-10, resulted in RhoA activation and RhoA-dependent gene expression through the Gαq-p63RhoGEF signaling pathway. Anchorage-independent growth was tightly linked to dose-dependent regulation of RhoA by Kiss1r. In support of these results, siRNA-mediated knockdown of KISS1R or inactivation of RhoA in human MCF10A breast epithelial cells overexpressing H-RasV12 was sufficient to reduce Ras-induced anchorage-independent growth. In summary, we concluded that Kiss1r attenuation was sufficient to delay breast tumor initiation, progression, and metastasis through inhibitory effects on the downstream Gαq-p63RhoGEF-RhoA signaling pathway.
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Affiliation(s)
- Sung-Gook Cho
- Center for Cancer and Stem Cell Biology, Institute of Bioscience and Technology, Texas A&M System Health Science Center, Houston, Texas 77030, USA
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92
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de Ronde W, Tostevin F, ten Wolde PR. Multiplexing biochemical signals. PHYSICAL REVIEW LETTERS 2011; 107:048101. [PMID: 21867046 DOI: 10.1103/physrevlett.107.048101] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Indexed: 05/31/2023]
Abstract
In this Letter we show that living cells can multiplex biochemical signals, i.e., transmit multiple signals through the same signaling pathway simultaneously, and yet respond to them very specifically. We demonstrate how two binary input signals can be encoded in the concentration of a common signaling protein, which is then decoded such that each of the two output signals provides reliable information about one corresponding input. Under biologically relevant conditions the network can reach the maximum amount of information that can be transmitted, which is 2 bits.
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Affiliation(s)
- Wiet de Ronde
- FOM Institute for Atomic and Molecular Physics (AMOLF), Science Park 104, 1098 XG Amsterdam, The Netherlands
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93
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UNC-73/trio RhoGEF-2 activity modulates Caenorhabditis elegans motility through changes in neurotransmitter signaling upstream of the GSA-1/Galphas pathway. Genetics 2011; 189:137-51. [PMID: 21750262 DOI: 10.1534/genetics.111.131227] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Rho-family GTPases play regulatory roles in many fundamental cellular processes. Caenorhabditis elegans UNC-73 RhoGEF isoforms function in axon guidance, cell migration, muscle arm extension, phagocytosis, and neurotransmission by activating either Rac or Rho GTPase subfamilies. Multiple differentially expressed UNC-73 isoforms contain a Rac-specific RhoGEF-1 domain, a Rho-specific RhoGEF-2 domain, or both domains. The UNC-73E RhoGEF-2 isoform is activated by the G-protein subunit Gαq and is required for normal rates of locomotion; however, mechanisms of UNC-73 and Rho pathway regulation of locomotion are not clear. To better define UNC-73 function in the regulation of motility we used cell-specific and inducible promoters to examine the temporal and spatial requirements of UNC-73 RhoGEF-2 isoform function in mutant rescue experiments. We found that UNC-73E acts within peptidergic neurons of mature animals to regulate locomotion rate. Although unc-73 RhoGEF-2 mutants have grossly normal synaptic morphology and weak resistance to the acetylcholinesterase inhibitor aldicarb, they are significantly hypersensitive to the acetylcholine receptor agonist levamisole, indicating alterations in acetylcholine neurotransmitter signaling. Consistent with peptidergic neuron function, unc-73 RhoGEF-2 mutants exhibit a decreased level of neuropeptide release from motor neuron dense core vesicles (DCVs). The unc-73 locomotory phenotype is similar to those of rab-2 and unc-31, genes with distinct roles in the DCV-mediated secretory pathway. We observed that constitutively active Gαs pathway mutations, which compensate for DCV-mediated signaling defects, rescue unc-73 RhoGEF-2 and rab-2 lethargic movement phenotypes. Together, these data suggest UNC-73 RhoGEF-2 isoforms are required for proper neurotransmitter signaling and may function in the DCV-mediated neuromodulatory regulation of locomotion rate.
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94
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Intracellular regulation of heterotrimeric G-protein signaling modulates vascular smooth muscle cell contraction. Arch Biochem Biophys 2011; 510:182-9. [DOI: 10.1016/j.abb.2011.05.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 05/05/2011] [Accepted: 05/14/2011] [Indexed: 12/28/2022]
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95
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Adjobo-Hermans MJW, Goedhart J, van Weeren L, Nijmeijer S, Manders EMM, Offermanns S, Gadella TWJ. Real-time visualization of heterotrimeric G protein Gq activation in living cells. BMC Biol 2011; 9:32. [PMID: 21619590 PMCID: PMC3129320 DOI: 10.1186/1741-7007-9-32] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 05/27/2011] [Indexed: 12/28/2022] Open
Abstract
Background Gq is a heterotrimeric G protein that plays an important role in numerous physiological processes. To delineate the molecular mechanisms and kinetics of signalling through this protein, its activation should be measurable in single living cells. Recently, fluorescence resonance energy transfer (FRET) sensors have been developed for this purpose. Results In this paper, we describe the development of an improved FRET-based Gq activity sensor that consists of a yellow fluorescent protein (YFP)-tagged Gγ2 subunit and a Gαq subunit with an inserted monomeric Turquoise (mTurquoise), the best cyan fluorescent protein variant currently available. This sensor enabled us to determine, for the first time, the kon (2/s) of Gq activation. In addition, we found that the guanine nucleotide exchange factor p63RhoGEF has a profound effect on the number of Gq proteins that become active upon stimulation of endogenous histamine H1 receptors. The sensor was also used to measure ligand-independent activation of the histamine H1 receptor (H1R) upon addition of a hypotonic stimulus. Conclusions Our observations reveal that the application of a truncated mTurquoise as donor and a YFP-tagged Gγ2 as acceptor in FRET-based Gq activity sensors substantially improves their dynamic range. This optimization enables the real-time single cell quantification of Gq signalling dynamics, the influence of accessory proteins and allows future drug screening applications by virtue of its sensitivity.
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Affiliation(s)
- Merel J W Adjobo-Hermans
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
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Somatostatin inhibits cell migration and reduces cell counts of human keratinocytes and delays epidermal wound healing in an ex vivo wound model. PLoS One 2011; 6:e19740. [PMID: 21589940 PMCID: PMC3092774 DOI: 10.1371/journal.pone.0019740] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 04/14/2011] [Indexed: 12/26/2022] Open
Abstract
The peptide hormone somatostatin (SST) and its five G protein-coupled receptors
(SSTR1-5) were described to be present in the skin, but their cutaneous
function(s) and skin-specific signalling mechanisms are widely unknown. By using
receptor specific agonists we show here that the SSTRs expressed in
keratinocytes are functionally coupled to the inhibition of adenylate cyclase.
In addition, treatment with SSTR4 and SSTR5/1 specific agonists significantly
influences the MAP kinase signalling pathway. As epidermal hormone receptors in
general are known to regulate re-epithelialization following skin injury, we
investigated the effect of SST on cell counts and migration of human
keratinocytes. Our results demonstrate a significant inhibition of cell
migration and reduction of cell counts by SST. We do not observe an effect on
apoptosis and necrosis. Analysis of signalling pathways showed that somatostatin
inhibits cell migration independent of its effect on cAMP. Migrating
keratinocytes treated with SST show altered cytoskeleton dynamics with delayed
lamellipodia formation. Furthermore, the activity of the small GTPase Rac1 is
diminished, providing evidence for the control of the actin cytoskeleton by
somatostatin receptors in keratinocytes. While activation of all receptors leads
to redundant effects on cell migration, only treatment with a SSTR5/1 specific
agonist resulted in decreased cell counts. In accordance with reduced cell
counts and impaired migration we observe delayed re-epithelialization in an
ex vivo wound healing model. Consequently, our experiments
suggest SST as a negative regulator of epidermal wound healing.
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97
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Molecular pharmacology, physiology, and structure of the P2Y receptors. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2011; 61:373-415. [PMID: 21586365 DOI: 10.1016/b978-0-12-385526-8.00012-6] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The P2Y receptors are a widely expressed group of eight nucleotide-activated G protein-coupled receptors (GPCRs). The P2Y(1)(ADP), P2Y(2)(ATP/UTP), P2Y(4)(UTP), P2Y(6)(UDP), and P2Y(11)(ATP) receptors activate G(q) and therefore robustly promote inositol lipid signaling responses. The P2Y(12)(ADP), P2Y(13)(ADP), and P2Y(14)(UDP/UDP-glucose) receptors activate G(i) leading to inhibition of adenylyl cyclase and to Gβγ-mediated activation of a range of effector proteins including phosphoinositide 3-kinase-γ, inward rectifying K(+) (GIRK) channels, phospholipase C-β2 and -β3, and G protein-receptor kinases 2 and 3. A broad range of physiological responses occur downstream of activation of these receptors ranging from Cl(-) secretion by epithelia to aggregation of platelets to neurotransmission. Useful structural models of the P2Y receptors have evolved from extensive genetic analyses coupled with molecular modeling based on three-dimensional structures obtained for rhodopsin and several other GPCRs. Selective ligands have been synthesized for most of the P2Y receptors with the most prominent successes attained with highly selective agonist and antagonist molecules for the ADP-activated P2Y(1) and P2Y(12) receptors. The widely prescribed drug, clopidogrel, which results in irreversible blockade of the platelet P2Y(12) receptor, is the most important therapeutic agent that targets a P2Y receptor.
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98
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Wuertz CM, Lorincz A, Vettel C, Thomas MA, Wieland T, Lutz S. p63RhoGEF—a key mediator of angiotensin II‐dependent signaling and processes in vascular smooth muscle cells. FASEB J 2010. [DOI: 10.1096/fj.10.155499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Christina M. Wuertz
- Institute of Experimental and Clinical Pharmacology and Toxicology Heidelberg Germany
| | - Akos Lorincz
- Institute of Experimental and Clinical Pharmacology and Toxicology Heidelberg Germany
| | - Christiane Vettel
- Institute of Experimental and Clinical Pharmacology and Toxicology Heidelberg Germany
| | - Martin A. Thomas
- Institute of Experimental and Clinical Pharmacology and Toxicology Heidelberg Germany
| | - Thomas Wieland
- Institute of Experimental and Clinical Pharmacology and Toxicology Heidelberg Germany
| | - Susanne Lutz
- Medical Faculty MannheimUniversity of Heidelberg Heidelberg Germany
- Department of PharmacologyMedical Faculty Goettingen, University of Goettingen Goettingen Germany
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99
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Temple BRS, Jones CD, Jones AM. Evolution of a signaling nexus constrained by protein interfaces and conformational States. PLoS Comput Biol 2010; 6:e1000962. [PMID: 20976244 PMCID: PMC2954821 DOI: 10.1371/journal.pcbi.1000962] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 09/17/2010] [Indexed: 01/03/2023] Open
Abstract
Heterotrimeric G proteins act as the physical nexus between numerous receptors that respond to extracellular signals and proteins that drive the cytoplasmic response. The Gα subunit of the G protein, in particular, is highly constrained due to its many interactions with proteins that control or react to its conformational state. Various organisms contain differing sets of Gα-interacting proteins, clearly indicating that shifts in sequence and associated Gα functionality were acquired over time. These numerous interactions constrained much of Gα evolution; yet Gα has diversified, through poorly understood processes, into several functionally specialized classes, each with a unique set of interacting proteins. Applying a synthetic sequence-based approach to mammalian Gα subunits, we established a set of seventy-five evolutionarily important class-distinctive residues, sites where a single Gα class is differentiated from the three other classes. We tested the hypothesis that shifts at these sites are important for class-specific functionality. Importantly, we mapped known and well-studied class-specific functionalities from all four mammalian classes to sixteen of our class-distinctive sites, validating the hypothesis. Our results show how unique functionality can evolve through the recruitment of residues that were ancestrally functional. We also studied acquisition of functionalities by following these evolutionarily important sites in non-mammalian organisms. Our results suggest that many class-distinctive sites were established early on in eukaryotic diversification and were critical for the establishment of new Gα classes, whereas others arose in punctuated bursts throughout metazoan evolution. These Gα class-distinctive residues are rational targets for future structural and functional studies.
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Affiliation(s)
- Brenda R S Temple
- R. L. Juliano Structural Bioinformatics Core Facility, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
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100
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Wuertz CM, Lorincz A, Vettel C, Thomas MA, Wieland T, Lutz S. p63RhoGEF--a key mediator of angiotensin II-dependent signaling and processes in vascular smooth muscle cells. FASEB J 2010; 24:4865-76. [PMID: 20739613 DOI: 10.1096/fj.10-155499] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The purpose of our study was to investigate the role of endogenous p63RhoGEF in G(q/11)-dependent RhoA activation and signaling in rat aortic smooth muscle cells (RASMCs). Therefore, we studied the expression and subcellular localization in freshly isolated RASMCs and performed loss of function experiments to analyze its contribution to RhoGTPase activation and functional responses such as proliferation and contraction. By this, we could show that p63RhoGEF is endogenously expressed in RASMCs and acts there as the dominant mediator of the fast angiotensin II (ANG II)-dependent but not of the sphingosine-1-phosphate (S(1)P)-dependent RhoA activation. p63RhoGEF is not an activator of the concomitant Rac1 activation and functions independently of caveolae. The knockdown of endogenous p63RhoGEF significantly reduced the mitogenic response of ANG II, abolished ANG II-induced stress fiber formation and cell elongation in 2-D culture, and impaired the ANG II-driven contraction in a collagen-based 3-D model. In conclusion, our data provide for the first time evidence that p63RhoGEF is an important mediator of ANG II-dependent RhoA activation in RASMCs and therewith a leading actor in the subsequently triggered cellular processes, such as proliferation and contraction.
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Affiliation(s)
- Christina M Wuertz
- Institute of Experimental and Clinical Pharmacology and Toxicology, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
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