151
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Irita K, Fujita I, Takeshige K, Minakami S, Yoshitake J. Calcium channel antagonist induced inhibition of superoxide production in human neutrophils. Mechanisms independent of antagonizing calcium influx. Biochem Pharmacol 1986; 35:3465-71. [PMID: 3021172 DOI: 10.1016/0006-2952(86)90613-1] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Three calcium channel antagonists, verapamil, diltiazem and nisoldipine, inhibited superoxide production in human neutrophils that were stimulated by phorbol 12-myristate 13-acetate (PMA) in a buffered saline lacking calcium. Concentrations of these drugs giving 50% control activity (IC50) were 0.3, 0.45 and 0.01 mM respectively. This inhibition was also observed in the presence of ethylene glycol bis (beta-aminoethyl ether)-N,N'-tetraacetic acid (EGTA) and was not reversed by the addition of calcium. This suggests that calcium channel antagonists inhibited superoxide production independently of extracellular calcium. These calcium channel antagonists inhibited the mobilization of membrane-associated calcium, and protein phosphorylation probably catalyzed by C-kinase, both of which are thought to be involved in the signal transmission for the induction of superoxide production. Calcium channel antagonists also inhibited NADPH oxidase, responsible for superoxide production, with IC50 = 0.5, 3 and more than 0.08 mM, respectively, for verapamil, diltiazem and nisoldipine. The results indicate that calcium channel antagonists inhibit superoxide production by affecting not only the catalytic activity by also the activation of NADPH oxidase. Inhibition of superoxide production by calcium channel antagonists suggests that these antagonists do not affect cell functions merely by affecting calcium influx.
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152
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Protein kinase C and phosphatidylserine bind to Mr 110,000/115,000 polypeptides enriched in cytoskeletal and postsynaptic density preparations. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(18)69308-1] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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153
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Makowske M, Birnbaum MJ, Ballester R, Rosen OM. A cDNA encoding protein kinase C identifies two species of mRNA in brain and GH3 cells. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(18)67027-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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154
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Hermon J, Azrad A, Reiss N, Naor Z. Phospholipid-dependent Ca2+-activated protein kinase (C-kinase) in the pituitary: further characterization and endogenous redistribution. Mol Cell Endocrinol 1986; 47:201-8. [PMID: 3758474 DOI: 10.1016/0303-7207(86)90113-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Phospholipid-dependent, Ca2+-activated protein kinase (C-kinase) was recently shown to be expressed in rat pituitary. The enzyme is activated by Ca2+ and phosphatidylserine (PS). Diacylglycerol (DG), which is liberated during phosphoinositide turnover, and the potent tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate (TPA) activate pituitary C-kinase in the presence of PS, even at resting levels of intracellular Ca2+ (10(-7) M), and increase the apparent affinity of the enzyme for Ca2+. While micromolar concentration of Ca2+ had no effect on the apparent affinity of the enzyme for PS (Km approximately 15 micrograms/ml), elevation of Ca2+ to the millimolar range produced a sharp increase in the apparent affinity for PS (Km approximately 5 micrograms/ml). Elevation of PS (up to 500 micrograms/ml) could not replace Ca2+ in supporting maximal enzyme activity even in the presence of DG. Cytosolic pituitary C-kinase (70% of total enzyme activity) is recovered in an inactive state and can be activated without further purification. The particulate enzyme (30%) is recovered in a cofactors-insensitive form but can be activated after detergent-solubilization and anion exchange chromatography. Endogenous redistribution of soluble pituitary C-kinase to the membrane does not convert it to its proteolytic product which is insensitive to Ca2+, PS and DG. Pituitary C-kinase characterized here most likely plays a key role in signal transduction mechanisms involved in pituitary functions.
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155
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Protein phosphorylation and protein kinase activities in BC3H-1 myocytes. Differences between the effects of insulin and phorbol esters. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(18)67156-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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156
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Hirota K, Hirota T, Aguilera G, Catt KJ. Gonadotropin release and redistribution of calcium-activated, phospholipid-dependent protein kinase in phorbol-stimulated rat pituitary cells. Arch Biochem Biophys 1986; 249:557-62. [PMID: 3753017 DOI: 10.1016/0003-9861(86)90033-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The effect of phorbol esters on calcium-activated, phospholipid-dependent kinase (protein kinase C) and luteinizing hormone (LH) secretion was examined in cultured rat anterior pituitary cells. The potent tumor promoter 12-O-tetra-decanoylphorbol-13-acetate (TPA) stimulated LH secretion and activated pituitary protein kinase C in the presence of calcium and phosphatidylserine. The enzyme activity present in cytosol and particulate fractions was eluted at about 0.05 M NaCl during DE52-cellulose chromatography. Preincubation of pituitary cells with TPA markedly decreased cytosolic protein kinase C activity and increased enzyme activity in the particulate fraction. The maximal TPA-induced change in enzyme activity, with a 76% decrease in cytosol and a 4.3-fold increase in the particulate fraction, occurred within 10 min. The dose-dependent changes in protein kinase C redistribution in TPA-treated cells were correlated with the stimulation of LH release by the phorbol ester. These results suggest that activation of protein kinase C by TPA is associated with intracellular redistribution of the enzyme and is related to the process of secretory granule release from gonadotrophs.
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157
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Naor Z, Azrad A, Limor R, Zakut H, Lotan M. Gonadotropin-releasing hormone activates a rapid Ca2+-independent phosphodiester hydrolysis of polyphosphoinositides in pituitary gonadotrophs. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(18)67116-9] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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158
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Galbiati E, Calderini G, Viola G, Toffano G. Phorbol 12-myristate 13-acetate induces prolactin secretion from rat anterior pituitary gland by the activation of protein kinase-C. PHARMACOLOGICAL RESEARCH COMMUNICATIONS 1986; 18:687-98. [PMID: 3094041 DOI: 10.1016/0031-6989(86)90111-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The purpose of this study was to characterize the action of phorbol 12-myristate 13-acetate (PMA), a tumor-promoting agent, on rat anterior pituitary gland, focusing the attention on prolactin secretion. PMA elicited a significant increase in prolactin secretion without affecting phosphatidylinositol turnover, considered as an early post-receptor event controlling PRL secretion. However incubation of anterior pituitary glands with PMA caused a loss of protein kinase-C activity in cytoplasm concomitant with an increased enzyme activity in the membrane. The action of PMA on prolactin secretion seems to be mainly dependent from the redistribution and activation of protein kinase-C. In fact, the phorbol ester did not affect pituitary cAMP and cGMP metabolism either in basal conditions or after theophylline.
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159
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Abstract
Protein kinase C, an enzyme that is activated by the receptor-mediated hydrolysis of inositol phospholipids, relays information in the form of a variety of extracellular signals across the membrane to regulate many Ca2+-dependent processes. At an early phase of cellular responses, the enzyme appears to have a dual effect, providing positive forward as well as negative feedback controls over various steps of its own and other signaling pathways, such as the receptors that are coupled to inositol phospholipid hydrolysis and those of some growth factors. In biological systems, a positive signal is frequently followed by immediate negative feedback regulation. Such a novel role of this protein kinase system seems to give a logical basis for clarifying the biochemical mechanism of signal transduction, and to add a new dimension essential to our understanding of cell-to-cell communication.
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160
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Participation of voltage-dependent calcium channels in the action of gonadotropin-releasing hormone. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(18)67623-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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161
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Cossu G, Adamo S, Senni MI, Caporale C, Molinaro M. Altered distribution of protein kinase C in dystrophic muscle cells and its modulation by liposome-delivered phospholipids. Biochem Biophys Res Commun 1986; 137:752-8. [PMID: 3524563 DOI: 10.1016/0006-291x(86)91143-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The activity and subcellular distribution of the calcium-phospholipid dependent protein kinase (protein kinase C) were studied in normal and dystrophic muscle cells in vitro. Clonal strains of satellite cells, isolated from normal and dystrophic (C57BL/6J/dydy) mice, differentiate in vitro at a comparable level (over 80% of fusion). Differentiated myotubes were homogenized and separated into a soluble and a particulate fraction. The activity of protein kinase C was assayed in both fractions, and was found to be mainly in the cytosol of normal cells, whereas it was mainly associated to the membrane fraction of dystrophic cells. This altered distribution of the enzyme was likely consequent to alterations in the phospholipid composition of the dystrophic cell membrane, since it was possible to partially revert the situation by modifying the membranes with liposome-delivered phospholipids. Splenic lymphocytes from dystrophic mice showed an altered distribution of protein kinase C similar to that observed in muscle cells. The possible biochemical basis and the functional consequences of this altered distribution of the enzyme in the dystrophic cells are discussed.
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162
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Phorbol ester- and Ca2+-dependent phosphorylation of human red cell membrane skeletal proteins. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(19)57457-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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163
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Badwey JA, Robinson JM, Curnutte JT, Karnovsky MJ, Karnovsky ML. Retinoids stimulate the release of superoxide by neutrophils and change their morphology. J Cell Physiol 1986; 127:223-8. [PMID: 3009496 DOI: 10.1002/jcp.1041270206] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
All-trans-retinal stimulated the release of superoxide by human and guinea pig neutrophils 63 +/- 14 SD and 53 +/- 5 SD nmol of O2-/min/10(7) cells, respectively. Superoxide release by unstimulated cells was negligible. All-trans-retinal also induced morphological changes (i.e., evaginations) in these cells. Other retinoids were effective in instigating these phenomena. The similarities of these effects to those instigated by cis-unsaturated fatty acids (Badwey, J.A., et al., 1984, J. Biol. Chem., 259:7870-7877) are discussed in light of possible mechanisms.
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164
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Liles WC, Hunter DD, Meier KE, Nathanson NM. Activation of protein kinase C induces rapid internalization and subsequent degradation of muscarinic acetylcholine receptors in neuroblastoma cells. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(19)57215-5] [Citation(s) in RCA: 114] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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165
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Shoji M, Girard PR, Mazzei GJ, Vogler WR, Kuo JF. Immunocytochemical evidence for phorbol ester-induced protein kinase C translocation in HL60 cells. Biochem Biophys Res Commun 1986; 135:1144-9. [PMID: 3516146 DOI: 10.1016/0006-291x(86)91047-8] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The ability of tumor promoting 12-O-tetradecanoylphorbol-13-acetate (TPA) to redistribute protein kinase C in human promyelocytic leukemic HL60 cells was investigated. It was found that TPA caused a rapid translocation (within 10 min) of protein kinase C from the cytosolic (soluble) fraction to the particulate (membrane) fraction, as determined indirectly by assaying for the enzyme activity or by immunoblotting of the enzyme protein in the isolated subcellular fractions. Immunocytochemical localization of the enzyme demonstrated directly that the TPA caused an enzyme translocation t the plasma membrane. These findings suggest that translocation to the plasma membrane of the enzyme may represent initial events related to the TPA effect on terminal differentiation of HL60 cells to monocytes/macrophages.
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166
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Kiesel L, Bertges K, Rabe T, Runnebaum B. Gonadotropin releasing hormone enhances polyphosphoinositide hydrolysis in rat pituitary cells. Biochem Biophys Res Commun 1986; 134:861-7. [PMID: 3004468 DOI: 10.1016/s0006-291x(86)80499-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Addition of gonadotropin releasing hormone to myo-[2-3H]inositol-prelabeled rat pituitary cells in primary culture evoked a dose-dependent increase of the accumulation of [3H]inositol phosphates with a rise of inositol triphosphate within 30 sec of stimulation, followed by a rise in inositol diphosphate and inositol monophosphate. Inositol phosphate accumulation was enhanced up to 5-to-8-fold and was time-dependent between up to 15 min incubation without further increase beyond this time period. Without preincubation with LiCl2, there was no measurable increase of GnRH-induced inositol phosphate accumulation compared to controls. The presence of calcium in the incubation medium did not affect the increase of inositol phosphates. These data give evidence, that polyphosphoinositide breakdown may be an early step in the action of gonadotropin releasing hormone on gonadotropin secretion.
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167
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Chang JP, Graeter J, Catt KJ. Coordinate actions of arachidonic acid and protein kinase C in gonadotropin-releasing hormone-stimulated secretion of luteinizing hormone. Biochem Biophys Res Commun 1986; 134:134-9. [PMID: 3080984 DOI: 10.1016/0006-291x(86)90537-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The relative contributions of arachidonic acid and protein kinase C during GnRH-stimulated LH release were investigated in cultured rat anterior pituitary cells. Maximal or near-maximal concentrations of arachidonic acid or the phorbol ester, 12-O-tetradecanoylphorbol 13-acetate, were less effective than a maximal dose of GnRH in stimulating LH release. However, the effect of a combination of arachidonic acid and phorbol ester was equivalent with that of GnRH. The protein kinase C inhibitor, retinal, significantly reduced GnRH- and phorbol-induced, but not arachidonic acid-stimulated, LH release. The lipoxygenase inhibitors, 5,8,11,14-eicosatetraynoic acid and nordihydroguaiaretic acid, partially inhibited GnRH- and arachidonic acid-stimulated, but not phorbol-induced, LH secretion. Simultaneous addition of retinal and either lipoxygenase inhibitor completely abolished LH responses elicited by GnRH, as well as by combined treatment with arachidonic acid and the phorbol ester. These results suggest that hormone release is mediated by phospholipid-dependent mechanisms that are coordinated during the stimulation of LH secretion by GnRH.
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168
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Dunkley PR, Robinson PJ. Depolarization-dependent protein phosphorylation in synaptosomes: mechanisms and significance. PROGRESS IN BRAIN RESEARCH 1986; 69:273-93. [PMID: 3447232 DOI: 10.1016/s0079-6123(08)61065-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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169
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5 Protein Kinase C. ACTA ACUST UNITED AC 1986. [DOI: 10.1016/s1874-6047(08)60430-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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170
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Abstract
To elucidate the mechanisms of stimulatory actions of GnRH on rat granulosa cells (GC), we have compared the actions of a GnRH agonist with those of a tumor-promoting phorbol ester, 12-0-tetradecanoylphorbol 13-acetate (TPA) and Ca+2 ionophore, A23187. GC were obtained from immature (28-29 days old) rats 48 h after injection of 20 IU PMSG. Following prelabeling with 3[H]arachidonic acid (AA), the cells were incubated with the test substances for 10 min and AA release determined. A GnRH agonist, [D-Ala6, des-Gly-NH2(10)] GnRH ethylamide (GnRHa; 10 ng/ml) increased AA release 175% compared to the control value. AA release in the presence of GnRHa was larger than that due to 1 microM A23187 or 40 nM TPA alone. A23187 or TPA increased GnRHa-stimulated AA release further. GC were incubated with the test substances for longer time periods, i.e., up to 5 h. GnRHa caused a 4-fold increase in prostaglandin (PG) synthase activity at 5 h. GnRHa increased PGE accumulation to the same extent as TPA, but only increased PG synthase activity about half as much. In combination with TPA, GnRHa had no influence on TPA-stimulated PG synthase activity, but increased PGE accumulation to levels comparable to those with A23187 plus TPA. GnRHa caused a 2.5 fold increase in progesterone (P) accumulation, which was the same as TPA. P accumulation in the presence of GnRHa was affected by neither A23187 nor TPA. These data indicate that the combination of TPA and A23187 can substitute for GnRH action on PGE and P accumulation in rat GC.
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171
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Badwey JA, Karnovsky ML. Production of superoxide by phagocytic leukocytes: a paradigm for stimulus-response phenomena. CURRENT TOPICS IN CELLULAR REGULATION 1986; 28:183-208. [PMID: 3024909 DOI: 10.1016/b978-0-12-152828-7.50006-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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172
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Immunological quantitation of phospholipid/Ca2+-dependent protein kinase and its fragments. Tissue levels, subcellular distribution, and ontogenetic changes in brain and heart. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(17)42481-1] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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173
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Shinohara O, Knecht M, Feng P, Catt KJ. Activation of protein kinase C potentiates cyclic AMP production and stimulates steroidogenesis in differentiated ovarian granulosa cells. JOURNAL OF STEROID BIOCHEMISTRY 1986; 24:161-8. [PMID: 3009971 DOI: 10.1016/0022-4731(86)90046-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Gonadotropin-stimulated steroidogenesis in the differentiating ovarian granulosa cell is mediated through the activation of cAMP-dependent protein kinase, and is also modulated by calcium-dependent mechanisms. Granulosa cells contain calcium-activated, phospholipid-dependent protein kinase (C kinase), and show an increase in phosphatidylinositol turnover in response to GnRH agonist analogs. To evaluate the role of C kinase in ovarian steroidogenesis, the potent phorbol ester, TPA, and the permeant diacylglycerol, OAG, were used to activate C kinase in granulosa cells from PMSG-treated immature rats. Both TPA and OAG caused dose-dependent stimulation of progesterone production without affecting intra- or extracellular cAMP levels. However, the maximum steroid responses to these compounds were less than those stimulated by cAMP. The ED50 for TPA-stimulated progesterone production was 3 nM, which is close to the known Km for activation of C kinase. Stimulation of steroidogenesis was only observed with biologically-active phorbol esters and permeant diacylglycerols such as OAG and DOG. Exposure of granulosa cells to phospholipase C also increased progesterone production in a dose-dependent manner without changing the cAMP content. Although TPA and OAG did not increase basal cAMP production, both agents enhanced the cAMP responses stimulated by hCG and forskolin; likewise, phospholipase C alone did not change cAMP production but caused a dose-dependent increase in the cAMP responses to hCG and forskolin. These results demonstrate that activation of C kinase promotes steroidogenesis in ovarian granulosa cells, and potentiates the activation of adenylate cyclase by hCG and forskolin. Such findings support the possibility that the calcium, phospholipid-dependent enzyme could be involved in the regulation of progesterone production by hormonal ligands such as gonadotropins and GnRH.
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174
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Naor Z, Childs GV. Binding and activation of gonadotropin-releasing hormone receptors in pituitary and gonadal cells. INTERNATIONAL REVIEW OF CYTOLOGY 1986; 103:147-87. [PMID: 3017885 DOI: 10.1016/s0074-7696(08)60835-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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175
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Shinohara O, Knecht M, Catt KJ. Differential actions of phorbol ester and diacylglycerol on inhibition of granulosa cell maturation. Biochem Biophys Res Commun 1985; 133:468-74. [PMID: 3002344 DOI: 10.1016/0006-291x(85)90930-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Hormonal induction of granulosa cell maturation is inhibited by phorbol esters and permeant synthetic diacylglycerols, but these activators of protein kinase C differ in their effects on cAMP production and actions. Both agents prevented the induction of luteinizing hormone receptors and progesterone biosynthesis by follicle-stimulating hormone, choleragen, and forskolin, but only diacylglycerol abolished the cAMP responses to these stimuli. Granulosa cell aggregation and aromatase activity were inhibited by phorbol ester but not completely by diacylglycerol. In intact granulosa cells, cytosolic C kinase activity was rapidly decreased by phorbol ester but unaffected by diacylglycerol. Although diacylglycerol has a marked inhibitory action on cAMP production, the more prominent suppression of granulosa cell differentiation by phorbol ester may be related to its rapid and prolonged action on kinase C.
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176
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Palfrey HC, Waseem A. Protein kinase C in the human erythrocyte. Translocation to the plasma membrane and phosphorylation of bands 4.1 and 4.9 and other membrane proteins. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(17)36360-3] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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177
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Interaction of protein kinase C with membranes is regulated by Ca2+, phorbol esters, and ATP. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(17)36318-4] [Citation(s) in RCA: 195] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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178
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Abstract
Y-1 adrenal tumor cells and rat fasciculata cells were shown to possess an enzyme with the properties of protein kinase C. Activity was stimulated by Ca2+ and phospholipid (specifically phosphatidylserine). Enzyme activity was stimulated by addition of phorbol ester to a cell homogenate (ED50 10 nM) and inhibited by trifluoperazine (ID50 10 microM). ACTH and cyclic AMP added to Y-1 cells increased the activity of protein kinase C. Dose-response curves with ACTH showed that the hormone was effective in stimulating protein kinase C at lower concentrations than those required to increase steroid synthesis. When phorbol ester was added to Y-1 cells, total kinase C activity was diminished. Neither phorbol ester nor ACTH causes redistribution of protein kinase C between membranes and cytosol. Phorbol ester also stimulates steroid production by Y-1 cells. Protein kinase C phosphorylates 5 proteins in Y-1 cells (67, 61, 32, 16 and less than 14.4 kDa). Puromycin and cycloheximide increase the activity of protein kinase C in adrenal cells. It is concluded that protein kinase C may play an ancillary role in regulation of adrenal steroid synthesis but does not mediate the classical steroidogenic response that results from activation of adenylate cyclase by ACTH.
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179
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Ballester R, Rosen OM. Fate of immunoprecipitable protein kinase C in GH3 cells treated with phorbol 12-myristate 13-acetate. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(18)95721-2] [Citation(s) in RCA: 277] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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180
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Tanabe A, Nielsen TB, Rani CS, Field JB. Thyroid cell responses to thyrotropin and 12-O-tetradecanoyl-phorbol-13-acetate: translocation of protein kinase C and phosphorylation of thyroid cell polypeptide substrates. Arch Biochem Biophys 1985; 243:92-9. [PMID: 2415065 DOI: 10.1016/0003-9861(85)90776-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Not all of the effects of thyroid-stimulating hormone (TSH) on the thyroid are mediated by activation of the adenylate cyclase-cyclic AMP system, indicating that other control systems must also exist. Although a calcium-phospholipid-dependent protein kinase (protein kinase C) and specific substrates had been identified in thyroid tissue, their responsiveness to TSH and other stimulators has not been determined. In thyroid cells which had been preloaded with [32P]orthophosphate, TSH and 12-O-tetradecanoyl-phorbol-13-acetate (TPA) increased the phosphorylation of a 33K polypeptide substrate within 5 min in a dose-dependent fashion. The effect was observed with 1 mU/ml TSH and 3 nM TPA and was maximal with 100 mU/ml TSH and 100 nM TPA. The biologically inactive analog of TPA, 4 alpha-phorbol, had no effect. Isobutylmethylxanthine (IBMX) decreased the phosphorylation of the 33K polypeptide and inhibited the effect of TSH and TPA, indicating that the phosphorylation is not mediated by cyclic AMP. TSH and IBMX, but not TPA, augmented phosphorylation of a 38K polypeptide, suggesting involvement of cyclic AMP. In contrast TPA, but not TSH, increased the phosphorylation of 58K and 28K polypeptides. TSH, but not TPA or 4 alpha-phorbol, elevated the cyclic AMP level of thyroid slices. Incubation of thyroid slices with TSH or TPA significantly decreased protein kinase C activity in the 100,000g cytosol fraction and increased it in an extract of plasma membranes. The effect was present within 5 min and was maximal by 30 min. The effect was observed with 100 mU/ml TSH or 1 nM TPA. The stimulation by TSH or TPA of protein kinase C and its translocation from the cytosol to the plasma membranes of thyroid tissue may provide another mechanism for control of thyroid cell metabolism.
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181
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Naor Z, Kiesel L, Vanderhoek JY, Catt KJ. Mechanism of action of gonadotropin releasing hormone: role of lipoxygenase products of arachidonic acid in luteinizing hormone release. JOURNAL OF STEROID BIOCHEMISTRY 1985; 23:711-7. [PMID: 3001415 DOI: 10.1016/s0022-4731(85)80006-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The mechanism of action of gonadotropin-releasing hormone (GnRH) upon pituitary luteinizing hormone (LH) secretion has not yet been elucidated, but recent evidence has suggested that arachidonic acid or its metabolites are involved in GnRH action. In cultured rat pituitary cells, arachidonic acid and 5-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE) elicited concentration-dependent release of LH with EC50 of about 12 microM. Other lipoxygenase derivatives including 11-, 12- and 15-HETE, had no consistent effect on LH release, and leukotrienes (B4 and C4) exerted only minor stimulatory actions on LH release. The lipoxygenase inhibitors nordihydroguaiaretic acid (NDGA), 5,8,11,14-eicosatetraynoic acid (ETYA), and 3-amino-1-(3-trifluoromethyl phenyl)-2-pyrazoline hydrochloride (BW 755C) caused dose-dependent inhibition of GnRH-induced LH release, with IC50 values of 5, 8.5, and 175 microM, respectively. In contrast, the cyclooxygenase inhibitor, indomethacin, had a biphasic action on GnRH-stimulated LH release, with potentiation of GnRH action at low doses (up to 25 microM) and no effect at higher concentrations. These findings are consistent with the potential role of a 5-lipoxygenase product of arachidonic acid in the mechanism of action of GnRH on pituitary gonadotropin release.
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Catt KJ, Loumaye E, Wynn PC, Iwashita M, Hirota K, Morgan RO, Chang JP. GnRH receptors and actions in the control of reproductive function. JOURNAL OF STEROID BIOCHEMISTRY 1985; 23:677-89. [PMID: 3001412 DOI: 10.1016/s0022-4731(85)80003-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The hypothalamic control of reproductive function is expressed through the receptor-mediated actions of GnRH on the pituitary gonadotroph. GnRH receptors in the pituitary gland exhibit prominent variations in number during the ovarian cycle and after changes in steroid feedback, and are modulated by the rate of GnRH secretion from the hypothalamus. In cultured pituitary cells, GnRH receptors undergo down-regulation during exposure to GnRH agonists, followed by a subsequent elevation of sites that is dependent on protein synthesis. GnRH antagonists do not cause receptor down-regulation, but high-affinity antagonist analogs bind for extended periods to cause receptor occlusion and prolonged inhibition of GnRH action. Analysis of the rat pituitary GnRH receptor by photoaffinity labeling reveals two binding subunits of mol. wt 53,000 and 42,000. The receptor-activated processes leading to gonadotropin secretion are highly calcium-dependent, and are initiated by rapid phospholipid hydrolysis with production of arachidonic acid metabolites, diacylglycerol, and inositol phosphates. The role of protein kinase C in gonadotropin secretion is indicated by the ability of phorbol esters and synthetic diacylglycerols to stimulate LH release, the inhibition of protein kinase C and LH release by retinal, and the redistribution of protein kinase C between cytosol and membrane fractions during stimulation of pituitary gonadotrophs by GnRH. It is likely that the effects of arachidonate metabolites are integrated with those of calcium-calmodulin and calcium, phospholipid-dependent protein kinases during the immediate and sustained phases of GnRH-induced gonadotropin secretion.
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183
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Aberdam E, Dekel N. Activators of protein kinase C stimulate meiotic maturation of rat oocytes. Biochem Biophys Res Commun 1985; 132:570-4. [PMID: 2998374 DOI: 10.1016/0006-291x(85)91171-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Agonistic analogs of gonadotropin releasing hormone can induce oocyte maturation in rat follicle-enclosed oocytes (1-5). Cyclic AMP does not rise following exposure of the ovarian follicle to GnRH (3) suggesting that cAMP-dependent protein kinase is not involved in the mechanism of GnRH action in this system. Protein kinase C, which is independent of cAMP, has recently been reported to mediate GnRH action in the pituitary (6-8). The possible involvement of this enzyme in the regulation of oocyte maturation has been tested in the present study. We report here that phospholipase C and direct activators of protein kinase C can mimic the response of rat oocytes to GnRH. These results suggest that GnRH-induced meiotic maturation of rat oocytes is mediated by the phospholipid-dependent protein kinase, protein kinase C.
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184
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Perkins SN, Summers ST, Cronin MJ. Beta-adrenergic stimulation of anterior pituitary cyclic AMP is enhanced by tumor promoters. Endocr Res 1985; 11:181-90. [PMID: 2422024 DOI: 10.3109/07435808509032976] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Beta-adrenergic stimulation of cellular cyclic AMP accumulation was characterized in normal anterior pituitary cells in vitro. In the presence of isobutylmethylxanthine, the order of potency of catecholamine agonists, as well as the antagonism by propranolol and not phentolamine, aided in classifying the receptor as beta-adrenergic. Furthermore, this agonist effect was rapidly desensitized. Tumor promoters, which directly activate protein kinase C, enhanced the cyclic AMP levels achieved with beta-adrenergic agonists (1.5-fold average at 10 min). This acute effect occurred over 10-1000 nM phorbol dibutyrate or phorbol myristate acetate. Finally, 3H-phorbol dibutyrate binding to unstimulated anterior pituitary cells was predominantly associated with the cytosol (79%) versus membrane (21%) fractions. Thus, an acute role for protein kinase C in promoting beta-adrenergic receptor activation of adenylate cyclase activity is suggested for anterior pituitary cells.
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