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Chen HL, Cheng JY, Yang YF, Li Y, Jiang XH, Yang L, Wu L, Shi M, Liu B, Duan J, Li X, Li QW. Phospholipase C inhibits apoptosis of porcine oocytes cultured in vitro. J Cell Biochem 2020; 121:3547-3559. [DOI: 10.1002/jcb.29636] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 12/09/2019] [Indexed: 11/08/2022]
Affiliation(s)
- Hua Li Chen
- College of Animal Science and TechnologyNorthwest A&F UniversityYangling Shaanxi China
| | - Jian Yong Cheng
- College of Animal Science and TechnologyNorthwest A&F UniversityYangling Shaanxi China
| | - You Fu Yang
- College of Animal Science and TechnologyNorthwest A&F UniversityYangling Shaanxi China
| | - Yuan Li
- College of Animal Science and TechnologyNorthwest A&F UniversityYangling Shaanxi China
| | - Xiao Han Jiang
- College of Animal Science and TechnologyNorthwest A&F UniversityYangling Shaanxi China
| | - Li Yang
- College of Animal Science and TechnologyNorthwest A&F UniversityYangling Shaanxi China
| | - Lin Wu
- College of Animal Science and TechnologyNorthwest A&F UniversityYangling Shaanxi China
| | - Meihong Shi
- College of Animal Science and TechnologyNorthwest A&F UniversityYangling Shaanxi China
| | - Boyang Liu
- College of Animal Science and TechnologyNorthwest A&F UniversityYangling Shaanxi China
| | - Jiaxin Duan
- College of Animal Science and TechnologyNorthwest A&F UniversityYangling Shaanxi China
| | - Xiaoya Li
- College of Animal Science and TechnologyNorthwest A&F UniversityYangling Shaanxi China
| | - Qing Wang Li
- College of Animal Science and TechnologyNorthwest A&F UniversityYangling Shaanxi China
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2
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McCullar JS, Malencik DA, Vogel WK, Crofoot KM, Anderson SR, Filtz TM. Calmodulin potentiates G beta gamma activation of phospholipase C-beta3. Biochem Pharmacol 2007; 73:270-8. [PMID: 17118346 PMCID: PMC1866284 DOI: 10.1016/j.bcp.2006.10.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Revised: 10/05/2006] [Accepted: 10/09/2006] [Indexed: 11/25/2022]
Abstract
Phospholipase C-beta (PLC-beta) isozymes (EC 3.1.4.11) hydrolyze the membrane phospholipid phosphatidylinositol-4,5-bisphosphate to generate intracellular second messenger signaling molecules inositol-1,4,5-trisphosphate (IP3) and diacylglycerol (DAG) in response to receptor activation and other cellular stimuli. PLCbeta1 and PLCbeta3 isozymes were previously demonstrated to bind the calcium-sensitive molecule calmodulin [McCullar JS, Larsen SA, Millimaki RA, Filtz TM. Calmodulin is a phospholipase C-{beta} interacting protein. J Biol Chem 2003;278(36):33708-13]. We have now shown through fluorescence anisotropy that calmodulin/PLCbeta3 affinities increase with increasing calcium in a physiologically relevant concentration range. The bimolecular affinity constants for calmodulin interaction with PLCbeta1 or PLCbeta3 were estimated as 260 and 200 nM, respectively, from fluorescence anisotropy data. There was no effect of calmodulin on basal or G alpha q-stimulated catalytic activity for either isozyme. However, the interaction between calmodulin and PLCbeta3 leads to potentiation of activation by the G-protein beta gamma dimer in an in vitro assay. 1321N1 cells treated with calmodulin inhibitors concurrent with and post-stimulation of muscarinic receptors significantly reduced [3H]PIP hydrolysis. Together these data are suggestive of cooperative role for calmodulin in the G-protein beta gamma dimer-stimulated activity of PLCbeta3.
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Affiliation(s)
- Jennifer S McCullar
- Molecular and Cellular Biology Graduate Program, Oregon State University, Corvallis, OR 97331, USA
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3
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Soto X, Mayor R, Torrejón M, Montecino M, Hinrichs MV, Olate J. Gαq negatively regulates the Wnt-β-catenin pathway and dorsal embryonicXenopus laevis development. J Cell Physiol 2007; 214:483-90. [PMID: 17654482 DOI: 10.1002/jcp.21228] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The non-canonical Wnt/Ca2+ signaling pathway has been implicated in the regulation of axis formation and gastrulation movements during early Xenopus laevis embryo development, by antagonizing the canonical Wnt/beta-catenin dorsalizing pathway and specifying ventral cell fate. However, the molecular mechanisms involved in this antagonist crosstalk are not known. Since Galphaq is the main regulator of Ca2+ signaling in vertebrates and from this perspective probably involved in the events elicited by the non-canonical Wnt/Ca2+ pathway, we decided to study the effect of wild-type Xenopus Gq (xGalphaq) in dorso-ventral axis embryo patterning. Overexpression of xGalphaq or its endogenous activation at the dorsal animal region of Xenopus embryo both induced a strong ventralized phenotype and inhibited the expression of dorsal-specific mesoderm markers goosecoid and chordin. Dorsal expression of an xGalphaq dominant-negative mutant reverted the xGalphaq-induced ventralized phenotype. Finally, we observed that the Wnt8-induced secondary axis formation is reverted by endogenous xGalphaq activation, indicating that it is negatively regulating the Wnt/beta-catenin pathway.
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Affiliation(s)
- Ximena Soto
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Casilla 160-C, Universidad de Concepción, Concepción, Chile
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Wittmann S, Fröhlich D, Mietens A, Daniels S. Anaesthetic sensitivity of fMLP-induced cell signalling in Xenopus oocytes. Int Immunopharmacol 2005; 6:61-70. [PMID: 16332514 DOI: 10.1016/j.intimp.2005.07.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2005] [Revised: 04/26/2005] [Accepted: 07/27/2005] [Indexed: 10/25/2022]
Abstract
FMLP stimulation of Xenopus oocytes expressing fMLP receptors leads to a concentration-dependent biphasic inward current. To identify the evolution of these currents we have examined the effects of blocking various cell signalling pathways. In addition we have analysed the effects of three intravenous anaesthetics on these fMLP-induced currents. Xenopus oocytes were microinjected with cRNA encoding the fMLP receptor and fMLP-stimulated (100 nM) currents measured, using two-electrode voltage-clamp (-70 mV), before and after injection of heparin (120 ng ml-1), wortmannin (1 microM), U73122 (5 microM) or buffer. Concentration-response curves were established for the action on fMLP-stimulated currents of thiopentone (5-500 microM), methohexitone (0.2-200 microM) and propofol (0.5-500 microM). Heparin significantly enhanced the fast current (p<0.05). Wortmannin had no effect on either current. U73122 inhibited only the slow current (p<0.05). All anaesthetics inhibited both currents, with the maximum inhibition for the fast/slow currents 70%/100%, 60%/60% and 100%/100% for thiopentone (IC50 147/120 microM), methohexitone (IC50 4.7/2.2 microM) and propofol (IC50 33/8 microM), respectively. We suggest (a) the slow current arises via the PLC/PKC pathway because it is reduced by the PLC inhibitor U73122, (b) the PI3K- and PLD-mediated pathways are not involved because wortmannin had no effect and (c) activation of the two conductance channels must be different because U73122 reduced the slow but not the fast current. Since both currents are decreased by all three anaesthetics, their inhibition might be mediated through an action at the agonist/receptor, although, since the slow current is consistently more sensitive than the fast, there may be additionally an action on cell signalling.
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Affiliation(s)
- Sigrid Wittmann
- Department of Anaesthesiology, University of Regensburg, 93042 Regensburg, Germany.
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Uezono Y, Kaibara M, Murasaki O, Taniyama K. Involvement of G protein betagamma-subunits in diverse signaling induced by G(i/o)-coupled receptors: study using the Xenopus oocyte expression system. Am J Physiol Cell Physiol 2004; 287:C885-94. [PMID: 15151902 DOI: 10.1152/ajpcell.00125.2004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We studied the functions of betagamma-subunits of G(i/o) protein using the Xenopus oocyte expression system. Isoproterenol (ISO) elicited cAMP production and slowly activating Cl(-) currents in oocytes expressing beta(2)-adrenoceptor and the protein kinase A-dependent Cl(-) channel encoded by the cystic fibrosis transmembrane conductance regulator (CFTR) gene. 5-Hydroxytryptamine (5-HT), [d-Ala(2), d-Leu(5)]-enkephalin (DADLE), and baclofen enhanced ISO-induced cAMP levels and CFTR currents in oocytes expressing beta(2)-adrenoceptor-CFTR and 5-HT(1A) receptor (5-HT(1A)R), delta-opioid receptor, or GABA(B) receptor, respectively. 5-HT also enhanced pituitary adenylate cyclase activating peptide (PACAP) 38-induced cAMP levels and CFTR currents in oocytes expressing PACAP receptor, CFTR and 5-HT(1A)R. The 5-HT-induced enhancement of G(s)-coupled receptor-mediated currents was abrogated by pretreatment with pertussis toxin (PTX) and coexpression of G transducin alpha (G(t)alpha). The 5-HT-induced enhancement was further augmented by coexpression of the Gbetagamma-activated form of adenylate cyclase (AC) type II but not AC type III. Thus betagamma-subunits of G(i/o) protein contribute to the enhancement of G(s)-coupled receptor-mediated responses. 5-HT and DADLE did not elicit any currents in oocytes expressing 5-HT(1A)R or delta-opioid receptor alone. They elicited Ca(2+)-activated Cl(-) currents in oocytes coexpressing these receptors with the Gbetagamma-activated form of phospholipase C (PLC)-beta2 but not with PLC-beta1. These currents were inhibited by pretreatment with PTX and coexpression of G(t)alpha, suggesting that betagamma-subunits of G(i/o) protein activate PLC-beta2 and then cause intracellular Ca(2+) mobilization. Our results indicate that betagamma-subunits of G(i/o) protein participate in diverse intracellular signals, enhancement of G(s)-coupled receptor-mediated responses, and intracellular Ca(2+) mobilization.
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Affiliation(s)
- Yasuhito Uezono
- Department of Pharmacology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8523, Japan.
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6
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Penzo-Mendèz A, Umbhauer M, Djiane A, Boucaut JC, Riou JF. Activation of Gbetagamma signaling downstream of Wnt-11/Xfz7 regulates Cdc42 activity during Xenopus gastrulation. Dev Biol 2003; 257:302-14. [PMID: 12729560 DOI: 10.1016/s0012-1606(03)00067-8] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Wnt-11/Xfz7 signaling plays a major role in the regulation of convergent extension movements affecting the dorsal marginal zone (DMZ) of gastrulating Xenopus embryos. In order to provide data concerning the molecular targets of Wnt-11/Xfz7 signals, we have analyzed the regulation of the Rho GTPase Cdc42 by Wnt-11. In animal cap ectoderm, Cdc42 activity increases as a response to Wnt-11 expression. This increase is inhibited by pertussis toxin, or sequestration of free Gbetagamma subunits by exogenous Galphai2 or Galphat. Activation of Cdc42 is also produced by the expression of bovine Gbeta1 and Ggamma2. This process is abolished by a PKC inhibitor, while phorbol esther treatment of ectodermal explants activates Cdc42 in a PKC-dependent way, implicating PKC downstream of Gbetagamma. In activin-treated animal caps and in the embryo, interference with Gbetagamma signaling rescues morphogenetic movements inhibited by Wnt-11 hyperactivation, thus phenocopying the dominant negative version of Cdc42 (N(17)Cdc42). Conversely, expression of Gbeta1gamma2 blocks animal cap elongation. This effect is reversed by N(17)Cdc42. Together, our results strongly argue for a role of Gbetagamma signaling in the regulation of Cdc42 activity downstream of Wnt-11/Xfz7 in mesodermal cells undergoing convergent extension. This idea is further supported by the observation that expression of Galphat in the DMZ causes severe gastrulation defects.
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Affiliation(s)
- Alfredo Penzo-Mendèz
- Laboratoire de Biologie du Dévelopment, groupe Biologie Expérimentale, UMR CNRS 7622, Université Paris VI, 9 quai Saint-Bernard, 75005 Paris, France
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7
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Choi S, Kim HJ, Ko YS, Jeong SW, Kim YI, Simonds WF, Oh JW, Nah SY. G alpha(q/11) coupled to mammalian phospholipase C beta 3-like enzyme mediates the ginsenoside effect on Ca(2+)-activated Cl(-) current in the Xenopus oocyte. J Biol Chem 2001; 276:48797-802. [PMID: 11673455 DOI: 10.1074/jbc.m104346200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recently we demonstrated that ginsenosides, the active ingredients of Panax ginseng, enhanced Ca(2+)-activated Cl(-) current in the Xenopus oocyte through a signal transduction mechanism involving the activation of pertussis toxin-insensitive G protein and phospholipase C (PLC). However, it has not yet been determined precisely which G protein subunit(s) and which PLC isoform(s) participate in the ginsenoside signaling. To provide answers to these questions, we investigated the changes in ginsenoside effect on the Cl(-) current after intraoocyte injections of the cRNAs coding various G protein subunits, a regulator of G protein signaling (RGS2), and G beta gamma-binding proteins. In addition, we examined which of mammalian PLC beta 1-3 antibodies injected into the oocyte inhibited the action of ginsenosides on the Cl(-) current. Injection of G alpha(q) or G alpha(11) cRNA increased the basal Cl(-) current recorded 48 h after, and it further prevented ginsenosides from enhancing the Cl(-) current, whereas G alpha(i2) and G alpha(oA) cRNA injection had no significant effect. The changes following G alpha(q) cRNA injection were prevented when G beta(1)gamma(2) and G alpha(q) subunits were co-expressed by simultaneous injection of the cRNAs coding these subunits. Injection of cRNA coding G alpha(q)Q209L, a constitutively active mutant that does not bind to G beta gamma, produced effects similar to those of G alpha(q) cRNA injection. The effects of G alpha(q)Q209L cRNA injection, however, were not prevented by co-injection of G beta(1)gamma(2) cRNA. Injection of the cRNA coding RGS2, which interacts most selectively with G alpha(q/11) among various identified RGS isoforms and stimulates the hydrolysis of GTP to GDP in active GTP-bound G alpha subunit, resulted in a severe attenuation of ginsenoside effect on the Cl(-) current. Finally, antibodies against PLC beta 3, but not -beta 1 and -beta 2, markedly attenuated the ginsenoside effect examined at 3-h postinjection. These results suggest that G alpha(q/11) coupled to mammalian PLC beta 3-like enzyme mediates ginsenoside effect on Ca(2+)-activated Cl(-) current in the Xenopus oocyte.
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Affiliation(s)
- S Choi
- National Research Laboratory for the Study of Ginseng Signal Transduction and Department of Physiology, College of Veterinary Medicine, Chonnam National University, Kwangju 500-757 Korea
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8
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Kaibara M, Nagase Y, Murasaki O, Uezono Y, Doi Y, Taniyama K. GTP gamma S-induced Ca2+ activated Cl- currents: its stable induction by Gq alpha overexpression in Xenopus oocytes. JAPANESE JOURNAL OF PHARMACOLOGY 2001; 86:244-7. [PMID: 11459128 DOI: 10.1254/jjp.86.244] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In native Xenopus oocytes, injection of guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS) (30 mM, 5 nl) did not induce Cl- current in 11 out of 22 oocytes. Injection of increased concentration of GTPgammaS (100 mM, 5 nl) into the oocytes induced Cl- currents in 16 out of 17 oocytes; however, the size of the induced currents was extremely varied. In oocytes overexpressing Gq alpha, GTPgammaS (30 mM, 5 nl) faithfully evoked Ca2+-activated Cl- currents. These results indicate that heterogeneous expression of Gq alpha in Xenopus oocytes provides a useful system for studying the functional roles of Gq alpha in regulating cellular events.
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Affiliation(s)
- M Kaibara
- Department of Pharmacology, Nagasaki University School of Medicine, Japan.
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9
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Mischel PS, Smith SG, Vining ER, Valletta JS, Mobley WC, Reichardt LF. The extracellular domain of p75NTR is necessary to inhibit neurotrophin-3 signaling through TrkA. J Biol Chem 2001; 276:11294-301. [PMID: 11150291 PMCID: PMC2693057 DOI: 10.1074/jbc.m005132200] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The TrkA receptor is activated primarily by nerve growth factor (NGF), but it can also be activated by high concentrations of neurotrophin 3 (NT-3). The pan-neurotrophin receptor p75(NTR) strongly inhibits activation of TrkA by NT-3 but not by NGF. To examine the role of p75(NTR) in regulating the specificity of TrkA signaling, we expressed both receptors in Xenopus oocytes. Application of NGF or NT-3 to oocytes expressing TrkA alone resulted in efflux of (45)Ca(2+) by a phospholipase C-gamma-dependent pathway. Coexpression of p75(NTR) with TrkA inhibited (45)Ca(2+) efflux in response to NT-3 but not NGF. The inhibitory effect on NT-3 activation of TrkA increased with increasing expression of p75(NTR). Coexpression of a truncated p75(NTR) receptor lacking all but the first 9 amino acids of the cytoplasmic domain inhibited NT-3 stimulation of (45)Ca(2+) efflux, whereas coexpression of an epidermal growth factor receptor/p75(NTR) chimera (extracellular domain of epidermal growth factor receptor with transmembrane and cytoplasmic domains of p75(NTR)) did not inhibit NT-3 signaling through TrkA. These studies demonstrated that the extracellular domain of p75(NTR) was necessary to inhibit NT-3 signaling through TrkA. Remarkably, p75(NTR) binding to NT-3 was not required to prevent signaling through TrkA, since occupying p75(NTR) with brain-derived neurotrophic factor or anti-p75 antibody (REX) did not rescue the ability of NT-3 to activate (45)Ca(2+) efflux. These data suggested a physical association between TrkA and p75(NTR). Documenting this physical interaction, we showed that p75(NTR) and TrkA could be coimmunoprecipitated from Xenopus oocytes. Our results suggest that the interaction of these two receptors on the cell surface mediated the inhibition of NT-3-activated signaling through TrkA.
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Affiliation(s)
- P S Mischel
- Departments of Pathology and Laboratory Medicine, UCLA, Los Angeles, California 90095-1732, USA.
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10
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Hollmann MW, Wieczorek KS, Berger A, Durieux ME. Local anesthetic inhibition of G protein-coupled receptor signaling by interference with Galpha(q) protein function. Mol Pharmacol 2001; 59:294-301. [PMID: 11160866 DOI: 10.1124/mol.59.2.294] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Although local anesthetics are considered primarily Na(+) channel blockers, previous studies suggest a common intracellular site of action on different G protein-coupled receptors. In the present study, we characterized this site for the LPA, m1 muscarinic, and trypsin receptor. Xenopus laevis oocytes expressing endogenous LPA and trypsin or recombinant m1 receptors were two-electrode voltage clamped. We studied LPA inhibition in the presence of ropivacaine stereoisomers to determine whether LA act on a protein site. Ropivacaine inhibited LPA signaling in a stereoselective and noncompetitive manner, suggesting a protein interaction. Antisense injection was used to characterize G protein alpha-subunits involved in mediation of LPA, m1, trypsin, and angiotensin(1A) receptor signaling. Lidocaine and its analog QX314 were injected into oocytes expressing these receptors to examine a potential role for specific G protein alpha-subunits as targets for LA. Galpha(q) was shown to be among the primary G protein subunits mediating the LPA, m1, and trypsin receptor signaling, all of which were inhibited to a similar degree by intracellular injected QX314 (424 x 10(-6) M). Since the angiotensin(1A) receptor, previously shown not to be affected by LA, was found not to signal via Galpha(q), but via Galpha(o) and Galpha(14), the intracellular effect of LA most likely takes place at the Galpha(q)-subunit.
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MESH Headings
- Amides/pharmacology
- Anesthetics, Local/pharmacology
- Animals
- Binding Sites
- Drug Interactions
- GTP-Binding Protein alpha Subunits, Gq-G11
- Heterotrimeric GTP-Binding Proteins/drug effects
- Heterotrimeric GTP-Binding Proteins/genetics
- Heterotrimeric GTP-Binding Proteins/metabolism
- Heterotrimeric GTP-Binding Proteins/physiology
- Lidocaine/analogs & derivatives
- Lidocaine/pharmacology
- Lysophospholipids/metabolism
- Oligonucleotides, Antisense/pharmacology
- Oocytes/drug effects
- Oocytes/metabolism
- Receptor, Angiotensin, Type 1
- Receptor, Muscarinic M1
- Receptors, Angiotensin/metabolism
- Receptors, Cell Surface/antagonists & inhibitors
- Receptors, G-Protein-Coupled
- Receptors, Lysophosphatidic Acid
- Receptors, Muscarinic/metabolism
- Ropivacaine
- Signal Transduction/drug effects
- Trypsin/metabolism
- Xenopus laevis
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Affiliation(s)
- M W Hollmann
- Department of Anesthesiology and Pain Management, University Hospital Maastricht, The Netherlands
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11
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Rebecchi MJ, Pentyala SN. Structure, function, and control of phosphoinositide-specific phospholipase C. Physiol Rev 2000; 80:1291-335. [PMID: 11015615 DOI: 10.1152/physrev.2000.80.4.1291] [Citation(s) in RCA: 725] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Phosphoinositide-specific phospholipase C (PLC) subtypes beta, gamma, and delta comprise a related group of multidomain phosphodiesterases that cleave the polar head groups from inositol lipids. Activated by all classes of cell surface receptor, these enzymes generate the ubiquitous second messengers inositol 1,4, 5-trisphosphate and diacylglycerol. The last 5 years have seen remarkable advances in our understanding of the molecular and biological facets of PLCs. New insights into their multidomain arrangement and catalytic mechanism have been gained from crystallographic studies of PLC-delta(1), while new modes of controlling PLC activity have been uncovered in cellular studies. Most notable is the realization that PLC-beta, -gamma, and -delta isoforms act in concert, each contributing to a specific aspect of the cellular response. Clues to their true biological roles were also obtained. Long assumed to function broadly in calcium-regulated processes, genetic studies in yeast, slime molds, plants, flies, and mammals point to specific and conditional roles for each PLC isoform in cell signaling and development. In this review we consider each subtype of PLC in organisms ranging from yeast to mammals and discuss their molecular regulation and biological function.
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Affiliation(s)
- M J Rebecchi
- Departments of Anesthesiology and Physiology and Biophysics, School of Medicine, State University of New York, Stony Brook, New York 11794, USA.
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12
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Kume S, Inoue T, Mikoshiba K. Galphas family G proteins activate IP(3)-Ca(2+) signaling via gbetagamma and transduce ventralizing signals in Xenopus. Dev Biol 2000; 226:88-103. [PMID: 10993676 DOI: 10.1006/dbio.2000.9849] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
During early embryonic development, IP(3)-Ca(2+) signaling transduces ventral signaling at the time of dorsoventral axis formation. To identify molecules functioning upstream in this signal pathway, we examined effects of a panel of inhibitory antibodies against Galphaq/11, Galphas/olf, or Galphai/o/t/z. While all these antibodies showed direct inhibition of their targets, their effects on redirection of the ventral mesoderm to a dorsal fate varied. Anti-Galphas/olf antibody showed strong induction of dorsal fate, anti-Galphai/o/t/z antibody did so weakly, and anti-Galphaq/11 antibody was without effect. Injection of betaARK, a Gbetagamma inhibitor, mimicked the dorsalizing effect of anti-Galphas/olf antibody, whereas injection of adenylyl cyclase inhibitors at a concentration which inhibited Galphas-coupled cAMP increase did not do so. The activation of Galphas-coupled receptor gave rise to Ca(2+) transients. All these results suggest that activation of the Galphas-coupled receptor relays dorsoventral signal to Gbetagamma, which then stimulates PLCbeta and then the IP(3)-Ca(2+) system. This signaling pathway may play a crucial role in transducing ventral signals.
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Affiliation(s)
- S Kume
- Mikoshiba Calciosignal Net Project, Exploratory Research for Advanced Technology, Japan Science and Technology Corporation, 2-28-8 Honkomagome, Bunkyo-ku, Tokyo, 113-0021, Japan
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Sato K, Tokmakov AA, Iwasaki T, Fukami Y. Tyrosine kinase-dependent activation of phospholipase Cgamma is required for calcium transient in Xenopus egg fertilization. Dev Biol 2000; 224:453-69. [PMID: 10926780 DOI: 10.1006/dbio.2000.9782] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In a previous study (K.-I. Sato et al., 1999, Dev. Biol. 209, 308-320), we presented evidence that a Src-related protein-tyrosine kinase (PTK), named Xyk, may act upstream of the calcium release in fertilization of the Xenopus egg. In the present study, we examined whether PTK activation of phospholipase Cgamma (PLCgamma) plays a role in the fertilization-induced calcium signaling. Immunoprecipitation studies show that Xenopus egg PLCgamma is tyrosine phosphorylated and activated within a few minutes after fertilization but not after A23187-induced egg activation. Consistently, we observed a fertilization-induced association of PLCgamma with Xyk activity that was not seen in A23187-activated eggs. A Src-specific PTK inhibitor, PP1, blocked effectively the fertilization-induced association of PLCgamma with Xyk activity and up-regulation of PLCgamma, when microinjected into the egg. In addition, a PLC inhibitor, U-73122, inhibited sperm-induced inositol 1,4,5-trisphosphate production and the calcium transient and subsequent calcium-dependent events such as cortical contraction, elevation of fertilization envelope, and tyrosine dephosphorylation of p42 MAP kinase, all of which were also inhibited by PP1. On the other hand, A23187 could cause the calcium response and calcium-dependent events in eggs injected with PP1 or U-73122. These results support the idea that Xenopus egg fertilization requires Src-family PTK-dependent PLCgamma activity that acts upstream of the calcium-dependent signaling pathway.
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Affiliation(s)
- K Sato
- Laboratory of Molecular Biology, Biosignal Research Center, Kobe University, Nada, Japan.
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14
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Kobrinsky E, Spielman AI, Rosenzweig S, Marks AR. Ceramide triggers intracellular calcium release via the IP(3) receptor in Xenopus laevis oocytes. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:C665-72. [PMID: 10516096 DOI: 10.1152/ajpcell.1999.277.4.c665] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ceramide, a product of sphingomyelin turnover, is a lipid second messenger that mediates diverse signaling pathways, including those leading to cell cycle arrest and differentiation. The mechanism(s) by which ceramide signals downstream events have not been fully elucidated. Here we show that, in Xenopus laevis oocytes, ceramide-induced maturation is associated with the release of intracellular calcium stores. Ceramide caused a dose-dependent elevation in the second messenger inositol 1,4,5-trisphosphate (IP(3)) via activation of G(q/11)alpha and phospholipase C-betaX. Elevation of IP(3), in turn, activated the IP(3) receptor calcium release channel on the endoplasmic reticulum, resulting in a rise in cytoplasmic calcium. Thus our study demonstrates that cross talk between the ceramide and phosphoinositide signaling pathways modulates intracellular calcium homeostasis.
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Affiliation(s)
- E Kobrinsky
- Molecular Cardiology Program, Division of Cardiology, Department of Medicine, Columbia University College of Physicians and Surgeons, New York 10032, USA
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15
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Sheldahl LC, Park M, Malbon CC, Moon RT. Protein kinase C is differentially stimulated by Wnt and Frizzled homologs in a G-protein-dependent manner. Curr Biol 1999; 9:695-8. [PMID: 10395542 DOI: 10.1016/s0960-9822(99)80310-8] [Citation(s) in RCA: 391] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In studies of developmental signaling pathways stimulated by the Wnt proteins and their receptors, Xenopus Wnt-5A (Xwnt-5A) and a prospective Wnt receptor, rat Frizzled 2 (Rfz2), have been shown to stimulate inositol signaling and Ca2+ fluxes in zebrafish [1] [2] [3]. As protein kinase C (PKC) isoforms can respond to Ca2+ signals [4], we asked whether expression of different Wnt and Frizzled homologs modulates PKC. Expression of Rfz2 and Xwnt-5A resulted in translocation of PKC to the plasma membrane, whereas expression of rat Frizzled 1 (Rfz1), which activates a Wnt pathway using beta-catenin but not Ca2+ fluxes [5], did not. Rfz2 and Xwnt-5A were also able to stimulate PKC activity in an in vitro kinase assay. Agents that inhibit Rfz2-induced signaling through G-protein subunits blocked Rfz2-induced translocation of PKC. To determine if other Frizzled homologs differentially stimulate PKC, we tested mouse Frizzled (Mfz) homologs for their ability to induce PKC translocation relative to their ability to induce the expression of two target genes of beta-catenin, siamois and Xnr3. Mfz7 and Mfz8 stimulated siamois and Xnr3 expression but not PKC activation, whereas Mfz3, Mfz4 and Mfz6 reciprocally stimulated PKC activation but not expression of siamois or Xnr3. These results demonstrate that some but not all Wnt and Frizzled signals modulate PKC localization and stimulate PKC activity via a G-protein-dependent mechanism. In agreement with other studies [1] [2] [3]. [6] [7] these data support the existence of multiple Wnt and Frizzled signaling pathways in vertebrates.
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Affiliation(s)
- L C Sheldahl
- Howard Hughes Medical Institute, Department of Pharmacology, Center for Developmental Biology, University of Washington School of Medicine, Seattle, Washington, 98195, USA
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16
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Noh SJ, Kim MJ, Shim S, Han JK. Different signaling pathway between sphingosine-1-phosphate and lysophosphatidic acid in Xenopus oocytes: functional coupling of the sphingosine-1-phosphate receptor to PLC-xbeta in Xenopus oocytes. J Cell Physiol 1998; 176:412-23. [PMID: 9648929 DOI: 10.1002/(sici)1097-4652(199808)176:2<412::aid-jcp20>3.0.co;2-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In Xenopus oocytes, both sphingosine-1-phosphate (S1P) and lysophosphatidic acid (LPA) activate Ca2+-dependent oscillatory Cl- currents by acting through membrane-bound receptors. External application of 50 microM S1P elicited a long-lasting oscillatory current that continued over 30 min from the beginning of oscillation, with 300 nA (n = 11) as a usual maximum peak of current, whereas 1-microM LPA treatment showed only transiently oscillating but more vigorous current responses, with 2,800 nA (n = 18) as a maximum peak amplitude. Both phospholipid-induced Ca2+-dependent Cl- currents were observed in the absence of extracellular Ca2+, were blocked by intracellular injection of the Ca2+ chelator, EGTA, and could not be elicited by treatment with thapsigargin, an inhibitor of endoplasmic reticulum (ER) Ca2+ ATPase. Intracellular Ca2+ release appeared to be from inositol 1,4,5-trisphosphate (IP3)-sensitive Ca2+ store, because Cl- currents were blocked by heparin injection. Pretreatment with the aminosteroid, U-73122, an inhibitor of G protein-mediated phospholipase C (PLC) activation, to oocytes inhibited the current responses evoked both by S1P and LPA. However, when they were injected with 10 ng of antisense oligonucleotide (AS-ODN) against Xenopus phospholipase C (PLC-xbeta), oocytes could not respond to S1P application, whereas they responded normally to LPA, indicating that the S1P signaling pathway goes through PLC-xbeta, whereas LPA signaling goes through another unknown PLC. To determine the types of G proteins involved, we introduced AS-ODNs against four types of G-protein alpha subunits that were identified in Xenopus laevis; G(q)alpha, G11alpha, G0alpha, and G(i1)alpha. Among AS-ODNs against the G alphas tested, AS-G(q)alpha and AS-G(i1)alpha to S1P and AS-G(q)alpha and AS-G11alpha to LPA specifically reduced current responses, respectively, to about 20-30% of controls. These results demonstrate that LPA and S1P, although they have similar structural features, release intracellular Ca2+ from the IP3-sensitive pool, use different components in their signal transduction pathways in Xenopus oocytes.
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MESH Headings
- Animals
- Antisense Elements (Genetics)
- Calcium/metabolism
- Calcium/pharmacology
- Chelating Agents/pharmacology
- Chlorides/metabolism
- Cyclooxygenase Inhibitors/pharmacology
- Dose-Response Relationship, Drug
- Egtazic Acid/pharmacology
- Enzyme Inhibitors/pharmacology
- Estrenes/pharmacology
- Female
- GTP-Binding Protein alpha Subunits, Gi-Go/genetics
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- GTP-Binding Protein alpha Subunits, Gs/genetics
- GTP-Binding Protein alpha Subunits, Gs/metabolism
- Inositol 1,4,5-Trisphosphate/metabolism
- Isoenzymes/metabolism
- Lysophospholipids/pharmacology
- Niflumic Acid/pharmacology
- Oligonucleotide Probes
- Oocytes/chemistry
- Oocytes/enzymology
- Patch-Clamp Techniques
- Periodicity
- Phospholipase C beta
- Pyrrolidinones/pharmacology
- RNA, Messenger/analysis
- Receptors, Cell Surface/physiology
- Receptors, G-Protein-Coupled
- Receptors, Lysophospholipid
- Signal Transduction/drug effects
- Signal Transduction/physiology
- Sphingosine/analogs & derivatives
- Sphingosine/pharmacology
- Thapsigargin/pharmacology
- Type C Phospholipases/metabolism
- Xenopus laevis
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Affiliation(s)
- S J Noh
- Department of Life Science, Pohang University of Science and Technology, South Korea
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17
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Rizzoti K, Paquereau L, Shaw A, Knibiehler B, Audigier Y. A constitutively activated mutant of galphaq down-regulates EP-cadherin expression and decreases adhesion between ectodermal cells at gastrulation. Mech Dev 1998; 76:19-31. [PMID: 9767085 DOI: 10.1016/s0925-4773(98)00106-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We have examined the expression and function of the heterotrimeric GTP-binding protein Gq during early Xenopus embryogenesis. Abundant XGalphaq transcripts were detected in oocytes and early embryos by Northern blot analysis. In situ hybridization revealed that these transcripts are confined to the animal hemisphere of the mature oocyte and to the presumptive ectoderm of cleaving embryos. Microinjection at the two-cell stage of alphaq and Q209Lalphaq, a constitutively activated mutant, causes a disruption in ectodermal cell adhesion at late gastrulation. Dissociation/reaggregation experiments performed on animal cap explants clearly demonstrate that the Q209Lalphaq-induced phenotype occurs after reaggregation of the explants with a time-course similar to that observed in whole embryos. RT-PCR experiments performed on the explants from Q209Lalphaq-injected embryos revealed a selective decrease in the amount of EP-cadherin mRNA. Co-injection of EP-cadherin RNA, but also E-cadherin RNA, rescued the disaggregated phenotype. These data emphasize the functional link between Gq protein-coupled signalling pathways and cadherin molecules in the ectodermal layer during the morphogenetic movements of gastrulation.
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Affiliation(s)
- K Rizzoti
- Unité INSERM U-397, CHU Rangueil, Institut L. Bugnard, Bât. L3, 1, avenue Jean-Poulhès, 31054, Toulouse Cédex, France
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18
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Matsumoto M, Kaibara M, Uezono Y, Izumi F, Sumikawa K, Sexton PM, Taniyama K. Function of the rat calcitonin receptors, C1a and C1b, expressed in Xenopus oocytes. Biochem Biophys Res Commun 1998; 242:484-91. [PMID: 9464242 DOI: 10.1006/bbrc.1997.7991] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The function of the cloned rat calcitonin receptors, C1a and C1b, was studied in Xenopus oocytes using the two-electrode voltage clamp method. In oocytes expressing the C1a receptors and the cystic fibrosis transmembrane conductance regulator (CFTR), C1a/ CFTR, application (30 sec) of either salmon calcitonin (sCT) or human calcitonin (hCT) activated currents through CFTR. In C1b/CFTR, sCT activated the currents, whereas hCT failed to elicit a response. The sCT induced currents in C1a/CFTR were similar in size to those in C1b/CFTR. Both the activation and the deactivation of sCT-induced currents were slower in C1a/ CFTR. In oocytes expressing C1a or C1b alone, application of relatively high concentrations of sCT induced small oscillatory inward currents. Application of hCT induced small inward currents in C1a alone, but failed to activate currents in C1b alone. These results demonstrate new insights into the signal transduction of calcitonin receptors.
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Affiliation(s)
- M Matsumoto
- Department of Pharmacology, Nagasaki University, School of Medicine, Japan
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