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Vallée S, Fouchier F, Braguer D, Marvaldi J, Champion S. Ribavirin-induced resistance to heat shock, inhibition of the Ras-Raf-1 pathway and arrest in G(1). Eur J Pharmacol 2000; 404:49-62. [PMID: 10980262 DOI: 10.1016/s0014-2999(00)00596-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Ribavirin [1-(beta-D-ribofuranosyl)1,2,4-triazole-3-carboxamide (virazole)], a specific inhibitor of inositide 5'-monophosphate dehydrogenase (IMPDH), induces a strong depletion of GTP pools in IGR39 cells. After a 3-day treatment, the cell cycle was reversibly arrested in G(0)/G(1), suggesting the involvement of GTP in the cell cycle process. The reduction of the GTP cell content modified the appearance of the microtubule network, as examined using immunofluorescence. However, the dynamics of repolymerisation were not altered. When arrested in G(0)/G(1), cells displayed a surprising resistance to a 3-h period of heat shock at 45 degrees C. Considering the lack of coimmunoprecipitation of p21ras with Raf-1, the reduction of the level of GTP-associated p21ras and the decrease of the activation of the extracellular signal-regulated protein kinases (ERK), also known as mitogen-activated protein (MAP) kinase, in ribavirin-treated cells, we suggest a possible relationship between the expression of heat-shock proteins and the change, in GTP-depleted cells, of the regulation of Raf kinase by ras protein.
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Affiliation(s)
- S Vallée
- Biochimie Cellulaire, UPRES-A 6032 CNRS, Faculté de Pharmacie, 27 Bd Jean Moulin, F-13385 Cedex 5, Marseille, France
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Downs SM. Involvement of purine nucleotide synthetic pathways in gonadotropin-induced meiotic maturation in mouse cumulus cell-enclosed oocytes. Mol Reprod Dev 1997; 46:155-67. [PMID: 9021747 DOI: 10.1002/(sici)1098-2795(199702)46:2<155::aid-mrd6>3.0.co;2-p] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
This study was carried out to test the hypothesis that purine nucleotide-generating pathways are required for ligand-stimulated oocyte maturation in meiotically arrested cumulus cell-enclosed oocytes. Oocytes from hormonally primed, immature mice were cultured overnight in Eagle's minimum essential medium containing dibutyryl cyclic AMP (dbcAMP) (to maintain meiotic arrest), plus either mycophenolic acid or alanosine (inhibitors of guanyl and adenyl nucleotide production, respectively). Follicle-stimulating hormone (FSH) was added either at the outset of culture or after a 3-hr preincubation period. Under either of these conditions, the inhibitors suppressed FSH induction of germinal vesicle breakdown (GVB). In addition, the potency of FSH as an inducer of GVB was reduced following the 3-hr preincubation period, but this could be prevented if nucleotide precursors such as hypoxanthine, guanosine, or adenosine were included during the first 3 hr. Furthermore, preincubation had little effect on FSH induction of GVB when hypoxanthine was used to maintain meiotic arrest for the entire culture period. The phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine, could not mimic this protective effect of hypoxanthine. Azaserine and aminopterin, inhibitors of purine de novo synthesis, blocked hormone-triggered maturation in dbcAMP-arrested oocytes, but had little effect on hypoxanthine-arrested oocytes. The effect of azaserine on dbcAMP-treated oocytes could be reversed by the inclusion of AICA riboside, a compound that can be taken up by cells and phosphorylated to form AICAR, which can enter the purine de novo pathway at a point distal to the sites of azaserine inhibition. FSH was stimulatory to purine de novo synthesis, while azaserine, aminopterin, hypoxanthine, and AICA riboside all suppressed de novo synthesis in the presence or absence of FSH, with dbcAMP having no effect. HPLC analysis of 14C-hypoxanthine metabolism in oocyte-cumulus cell complexes revealed that changes in the pattern of purine metabolism did not mediate the meiosis-inducing effect of FSH. These data support the conclusion that purine nucleotide-generating pathways are vital participants in the mechanism(s) regulating hormone-induced meiotic maturation, and that either the de novo or salvage pathway can fulfill this nucleotide requirement.
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Affiliation(s)
- S M Downs
- Department of Biology, Marquette University, Milwaukee, Wisconsin 53201-1881, USA
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3
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Fouchier F, Forget P, Bellan C, Marvaldi J, Champion S, Pichon J. The effects of ribavirin on the GTP level and the VIP receptor dynamic of human IGR39 cells. J Recept Signal Transduct Res 1996; 16:39-58. [PMID: 8771530 DOI: 10.3109/10799899609039940] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
GTP is one of the major cellular molecules involved in fundamental functions of cell life. Ribavirin, and antiviral and antitumoral agent, the primary site of action of which is the IMP deshydrogenase, was used in order to depress the intracellular GTP level. Consequential effects were tested on the property and dynamic of the VIP receptor on human melanoma IGR 39 cells. A concentration of 100 microM of Ribavirin reduced the intracelluar GTP level by more than 60% and induced a reversible growth arrest. Nevertheless this drug displayed no effect on: i) the VIP binding parameters (Kd and Bmax) of both high and low affinity receptors; ii) the cycling of the VIP receptor; iii) the based and VIP-stimulated cAMP production and iv) the subcellular GTP distribution. We show that Ribavirin, in the range of concentrations used, is very efficient to inhibit GTP synthesis in the human melanoma cell line IGR 39 and its growth, without affecting VIP receptor functions.
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Affiliation(s)
- F Fouchier
- Laboratoire Biochimie Cellulaire-URA CNRS 1924, Faculté de Pharmacie, Marseille, France
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Hatakeyama K, Harada T, Kagamiyama H. IMP dehydrogenase inhibitors reduce intracellular tetrahydrobiopterin levels through reduction of intracellular GTP levels. Indications of the regulation of GTP cyclohydrolase I activity by restriction of GTP availability in the cells. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)36747-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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6
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Metz S, Rabaglia M, Pintar T. Selective inhibitors of GTP synthesis impede exocytotic insulin release from intact rat islets. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)42308-3] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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7
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Lindau M, Gomperts BD. Techniques and concepts in exocytosis: focus on mast cells. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1071:429-71. [PMID: 1751542 DOI: 10.1016/0304-4157(91)90006-i] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- M Lindau
- Department of Physics, Free University Berlin, Germany
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8
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Davis HW, McDonald JM. Modulation of guanine nucleotide effects on the insulin receptor by MgCl2. Biochem Biophys Res Commun 1990; 171:53-9. [PMID: 2118351 DOI: 10.1016/0006-291x(90)91355-v] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Insulin binding to partially purified rat adipocyte insulin receptors is inhibited approximately 40-60 percent by 1 mM GTP-gamma-S in the presence of 2 mM MgCl2. However, in the presence of 10 mM MgCl2, GTP-gamma-S does not inhibit binding. Increasing MgCl2 from 0.5 to 10 mM enhances the phosphorylation of calmodulin catalyzed by the insulin receptor but also reduces the inhibition seen with 500 microM GTP-gamma-S. The reversal of the GTP-gamma-S-induced inhibition of calmodulin phosphorylation by high concentrations of MgCl2 appears to be due to an effect on the calmodulin molecule since MgCl2 has little effect on the inhibition of phosphorylation of histone Hf2b or poly (Glu4, Tyr1) induced by GTP-gamma-S. Our data suggest that there are at least two GTP-binding proteins associated with the insulin receptor, one that regulates insulin binding and is modulated by MgCl2 and one that regulates substrate phosphorylation and/or receptor-substrate coupling and is not altered by MgCl2.
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Affiliation(s)
- H W Davis
- Department of Pathology, University of Alabama, Birmingham 35294
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9
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Rizzo MT, Tricot G, Hoffman R, Jayaram HN, Weber G, Garcia JG, English D. Inosine monophosphate dehydrogenase inhibitors. Probes for investigations of the functions of guanine nucleotide binding proteins in intact cells. Cell Signal 1990; 2:509-19. [PMID: 1981974 DOI: 10.1016/0898-6568(90)90073-j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Taken together, the above reports indicate that the IMP dehydrogenase inhibitors are valuable probes for investigation of the biological functions of guanine nucleotides in intact cells. While these agents have minor effects on levels of other nucleotides and enzymes, non-specific effects can be monitored by addition of guanine or guanosine to provide substrates for the salvage pathway of guanine nucleotide synthesis. The most important question yet to be resolved in employing these agents is why incomplete depletion of intracellular guanine nucleotides results in such dramatic effects on G-protein function. Since the level of GTP in resting cells is approximately 0.5 mM, even a 90% reduction in GTP levels should leave enough nucleotide to adequately activate most known G-proteins, as the latter display high binding affinities for guanine nucleotides in cell free systems. Several explanations have been proposed to account for this disparity. Much of the intracellular guanine nucleotide may be bound or compartmentalized and therefore unable to interact with certain G-proteins. Possibly, G-proteins in the intracellular environment possess a much lower affinity for GTP that they do in cell free system. It may be to the cells' advantage that relatively minor fluctuations in levels of GTP result in pronounced alterations in the biological function of G-proteins as this effect may provide a physiologically important mechanism for the regulation of G-proteins in vivo. Further studies are necessary to clarify the mechanisms involved in the regulation of the biological function of G-proteins and oncogene products by guanine nucleotides in intact cells.
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Affiliation(s)
- M T Rizzo
- Department of Medicine, Indiana University School of Medicine, Indianapolis 46202-5121
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11
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Pathway of phospholipase C activation initiated with platelet-derived growth factor is different from that initiated with vasopressin and bombesin. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)37658-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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12
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Pall ML, Robertson CK. Growth regulation by GTP. Regulation of nucleotide pools in Neurospora by nitrogen and sulfur control systems. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)37937-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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13
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Quantitation of the guanine nucleotide binding regulatory protein Gs in S49 cell membranes using antipeptide antibodies to alpha s. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(19)76566-1] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Lambert B, Haye B, Antonicelli F, Jacquemin C. Activation of adenylate cyclase in rat fat cells promotes an increase in GTP content which controls the enzyme activity. Mol Cell Endocrinol 1988; 55:183-92. [PMID: 2833416 DOI: 10.1016/0303-7207(88)90133-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In previous studies, we demonstrated that the treatment of adipocytes with cholera toxin or Bordetella pertussis toxin (IAP) promoted an increase in the total guanosine triphosphate (GTP) content of the cells concomitant with the increase in cyclic adenosine monophosphate (AMP) level and the resulting lipolysis. In the present studies, we show that the acute challenge of fat cells with 1 microM isoproterenol (IPNE) is associated with a transient increase in GTP level (3-fold in 6 min). This increase may be attributed to an inhibition of the disposal of GTP or to a stimulation of its synthesis. To evaluate the actual role of GTP, we used virazole, an antitumor agent which inhibits inosinic acid dehydrogenase. After 2 h preincubation of the cells with 1 mM virazole, the effect of a 6 min challenge with 1 microM IPNE is decreased by 59% at the GTP level and by 42% in cyclic AMP production. One hour later, the resulting lipolytic efficiency is reduced by 57%. IAP treatment (10 micrograms/ml) produced its maximal effect on GTP and cyclic AMP levels and on lipolysis after 90 min incubation. The antilipolytic effect of 1 microM phenylisopropyladenosine (PIA) is almost abolished. When 1 mM virazole is added to the cell suspension to deplete the guanyl nucleotide pool, the resulting lipolysis due to IAP treatment is decreased by 85%, whereas GTP and cyclic AMP levels were decreased by 80 and 70%, respectively. We can conclude that the cyclic AMP synthesis in intact cells is accompanied by a parallel increase of their GTP content, whether the stimulation results from the activation of Gs or the inhibition of Gi. The reduction of the guanyl nucleotide pool under virazole results in a relatively less important inhibition of lipolysis when Gs is stimulated than when it is Gi.
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Affiliation(s)
- B Lambert
- Biochimie, Faculté des Sciences de Reims, France
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15
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Ehlert FJ. Correlation between the binding parameters of muscarinic agonists and their inhibition of adenylate cyclase activity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1988; 236:265-76. [PMID: 3071111 DOI: 10.1007/978-1-4757-5971-6_21] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- F J Ehlert
- Department of Pharmacology, College of Medicine, University of California, Irvine 92717
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16
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Gomperts BD, Cockcroft S, Howell TW, Nüsse O, Tatham PE. The dual effector system for exocytosis in mast cells: obligatory requirement for both Ca2+ and GTP. Biosci Rep 1987; 7:369-81. [PMID: 3315030 DOI: 10.1007/bf01362501] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The secretory process is a coordinated cellular response, initiated by occupation of surface receptors and comprising an ordered sequence of biochemical steps subject to multiple controls. Conceptually we can divide the sequence into two main sections comprising early, receptor-mediated events leading to generation of intracellular second messengers, and later events leading to membrane fusion and exocytosis. With the discovery that occupation of Ca2+ mobilising receptors leads to activation of polyphosphoinositide phosphodiesterase (PPI-pde) through the mediation of a G-protein (Gp), all the early events can be ascribed to the plasma membrane. Investigation of the exocytotic stage of secretion has been simplified by the use of permeabilised cells in which the composition of the cytosol can be precisely controlled. We have used streptolysin-O, a bacterial cytolysin which generates protein-sized pores in the plasma membrane, to investigate the exocytotic mechanism of rat mast cells. We find that in addition to the activation of PPI-dpe, GTP also acts in concert with Ca2+ at, or close to, the exocytotic site. Exocytosis can occur after substantial depletion of cytosol lactate dehydrogenase and 3-phosphoglycerate kinase indicating that soluble cytosol proteins are unlikely to play any role. There is no absolute requirement for ATP or phosphorylating nucleotide in exocytosis though when present the effective affinities of the two obligatory effectors (i.e. Ca2+ and GTP) are substantially enhanced.
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Affiliation(s)
- B D Gomperts
- Department of Experimental Pathology, University College London, UK
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17
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Mustelin T. GTP dependence of the transduction of mitogenic signals through the T3 complex in T lymphocytes indicates the involvement of a G-protein. FEBS Lett 1987; 213:199-203. [PMID: 3104085 DOI: 10.1016/0014-5793(87)81491-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The T3 molecule on the surface membrane of T lymphocytes is involved in the transduction of the proliferation signal generated by an interaction between the antigen receptor and an antigen, to the interior of the T cell. Mitogenic monoclonal antibodies against the T3 molecule and mitogenic lectins induce a rapid (within 5 min) protein synthesis-independent activation of ornithine decarboxylase (ODC) in human T lymphocytes. When T cells are selectively depleted of guanine nucleotides by treatment with mycophenolic acid, the early mitogen-induced activation of ODC is completely inhibited. The inhibition rapidly reverted on the addition of guanine a few minutes before the mitogenic stimulation, and even more rapidly by GTP directly introduced into the T cells by a transient membrane permeabilization. GTP can be substituted for by a non-hydrolyzable GTP analogue, GTP-gamma-S, which also induces ODC activity by itself in human T cells. These results suggest that a G-protein(s) is involved in the transduction of the proliferation signal in human T cells.
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18
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Aublin JL, Lambert B, Haye B, Jacquemin C, Champion S. Relationships between the GTP content and the TSH-stimulated adenylate cyclase activity of cultured thyroid cells. Mol Cell Endocrinol 1986; 45:11-20. [PMID: 3009247 DOI: 10.1016/0303-7207(86)90077-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The adenylate cyclase activity of a crude membrane fraction derived from cells cultured for 4 days in the presence of TSH (0.1 mU/ml), when acutely stimulated with 25 mU/ml, is 5-8 times higher than that derived from control cells. It has been suggested that changes in the intracellular content of GTP resulting from TSH chronic treatment were the cause of the modified responsiveness of the cyclase. To investigate this hypothesis, a method for GTP determination was developed. The steady-state concentration of GTP in 4-day TSH-treated cells is 2-3 times higher than in 4-day control cells. The increase in GTP content is concentration dependent between 5 and 500 microU/ml TSH in the culture medium. It presents a maximum on day 4 of culture, but remains elevated up to day 5. Nevertheless the GTP content is not the only factor controlling the cyclase activity, indeed the addition of 0.1 mM GTP to membranes from control cells does not increase the response up to the level reached by membranes from TSH-treated cells. Treatment of the cells with virazole, a drug inhibiting the biosynthesis of guanyl nucleotides, greatly decreases the GTP level, but is unable to suppress the positive effect of the TSH chronic treatment on adenylate cyclase activity. These results show that the increase in GTP level resulting from culture of the cells in the presence of minute amounts of TSH is not exclusively linked to adenylate cyclase responsiveness to TSH.
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Kiss Z, Zamfirova R. Protamine inhibits adenylate cyclase activity: a possible reason for the toxicity of protamine. EXPERIENTIA 1983; 39:1381-2. [PMID: 6653727 DOI: 10.1007/bf01990114] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Protamine is an effective inhibitor of the various activated forms of adenylate cyclase of liver plasma membranes. Inhibition of adenylate cyclase may account for its toxic but not its antitumor effects.
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Shechter Y, Reitman P, Hizi A. Evaluation of factors responsible for the inability of insulin to antagonize lipolysis due to high concentrations of catecholamines. Biochem Biophys Res Commun 1982; 109:776-85. [PMID: 6297490 DOI: 10.1016/0006-291x(82)92007-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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21
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Krall JF, Leshon SC, Frolich M, Jamgotchian N, Korenman SG. Adenylate cyclase activation. Characterization of guanyl nucleotide requirements by direct radioligand-binding methods. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)33861-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
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22
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Roth CW, Singh T, Pastan I, Gottesman MM. Rous sarcoma virus transformed cells are resistant to cyclic AMP. J Cell Physiol 1982; 111:42-8. [PMID: 6282904 DOI: 10.1002/jcp.1041110108] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A nontransformed line of Chinese hamster ovary (CHO) cells (Pollard and Stanners, 1979) has been transformed by the Schmidt-Ruppin subgroup D strain of Rous sarcoma virus (SR-RSV). SR-RSV transformed CHO cells are shown to differ from spontaneously transformed cells in that the virally transformed cells are more resistant to growth inhibition or changes in cell shape by 8-Br-cyclic AMP or cholera toxin. SR-RSV transformed rat (NRK) cells also have a reduced sensitivity to growth inhibition by 8-Br-cyclic AMP. Cyclic AMP-dependent protein kinase was examined in SR-RSV transformed CHO cells, but no differences in enzyme level, activation by cyclic AMP, chromatographic behavior, or its ability to phosphorylate endogenous proteins in whole cells could be detected. It is concluded that transformation of CHO and NRK cells by SR-RSV alters the cells in a manner different from spontaneous transformation, and that this alteration does not affect cAMP-dependent protein kinase activity.
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Bradham LS, Cheung WY. Nucleotide cyclases. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1982; 27:189-231. [PMID: 6124997 DOI: 10.1016/s0079-6603(08)60601-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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24
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Shane E, Gammon DE, Bilezikian JP. A cellular activator of catecholamine-sensitive adenylate cyclase in rat reticulocytes and erythrocytes: changes during reticulocyte development and effects on the beta receptor. Arch Biochem Biophys 1981; 208:418-25. [PMID: 6266347 DOI: 10.1016/0003-9861(81)90527-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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25
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Effect of ampiox and guanosine triphosphate on cyclic nucleotide content in muscle tissue in A zone of inflamation. Bull Exp Biol Med 1981. [DOI: 10.1007/bf00836369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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26
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Costantini MG, Johnson GS. Disproportionate accumulation of 18S and 28S ribosomal RNA in cultured normal rat kidney cells treated with picolinic acid or 5-methylnicotinamide. Exp Cell Res 1981; 132:443-51. [PMID: 6452285 DOI: 10.1016/0014-4827(81)90119-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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27
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Shain W, Carpenter DO. Mechanisms of synaptic modulation. INTERNATIONAL REVIEW OF NEUROBIOLOGY 1981; 22:205-50. [PMID: 6115826 DOI: 10.1016/s0074-7742(08)60294-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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28
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Johnson GS. Metabolism of NAD and N1-methylnicotinamide in growing and growth-arrested cells. EUROPEAN JOURNAL OF BIOCHEMISTRY 1980; 112:635-41. [PMID: 6450682 DOI: 10.1111/j.1432-1033.1980.tb06128.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Nicotinamide is metabolized primarily into NAD and N1-methylnicotinamide in cultured cells of normal rat kidney. The metabolic pathways for the nicotinamide metabolites are independently regulated and are influenced by the growth stage of the cells. N1-Methylnicotinamide levels are 1.5--2-fold elevated in cells growth-arrested by treatment with histidinol, thymidine, or picolinic acid, or by serum starvation. This increase is due to a more rapid rate of synthesis rather than decrease in excretion. The rates of both synthesis and degradation of NAD are increased in serum-starved cells so that the NAD concentration is the same as it is in growing cells. NAD and N1- methylnicotinamide levels are not significantly increased when the intracellular nicotinamide concentration is increased 20-fold by addition of excess nicotinamide to the culture medium, demonstrating that the size of the nicotinamide pool does not limit synthesis of these compounds. In medium containing normal amounts of nicotinamide, the apparent first-order rate constant for the decay of NAD, radioactively labeled in the nicotinamide moiety, is about 4 h-1. Labeled N1-methylnicotinamide is not metabolized, but rather is excreted into the medium with a first-order rate constant of 3.9 h-1. The rate of loss of label from NAD, but not from N1-methylnicotinamide, is increased about twofold by addition of excess nicotinamide to the culture medium. This could be explained by a dilution of a labeled nicotinamide pool which is formed during NAD degradation and which is recycled into NAD but not into N1-methylnicotinamide. The results demonstrate a rapid turnover of NAD at the bond joining nicotinamide and ADP-ribose, in agreement with previous studies. In addition, the results show that nicotinamide is metabolized into N1-methylnicotinamide with what appears to be a carefully regulated synthetic mechanism. The existence of significant amounts of N1-methylnicotinamide in cultured cells raises the question of the physiological importance of this compound.
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Pinkett M, Jaworski C, Evain D, Anderson W. Limited proteolysis eliminates guanine nucleotide inhibition of choleragen-activated adenylate cyclase. Possible basis for proteolytic stimulation of cyclic AMP production. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)43889-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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30
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Omrani GR, Gammon DE, Bilezikian JP. Regulation of catecholamine-responsive adenylate cyclase activity in rat reticulocyte membranes by endogenous factors: general characteristics and resolution into protein and nucleotide components. BIOCHIMICA ET BIOPHYSICA ACTA 1980; 629:455-69. [PMID: 7417506 DOI: 10.1016/0304-4165(80)90151-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A 100 000 X g soluble, supernatant fraction obtained from the hemolysate of rat reticulocytes was studied for its effect upon catecholamine-sensitive adenylate cyclase activity in reticulocyte membranes. The supernatant material, devoid of adenylate cyclase activity itself, amplified isoproterenol-dependent activity in responsive membranes and was an essential requirement for the expression of hormone sensitivity in membranes rendered unresponsive to isoproterenol alone. The increment in catecholamine-associated activity conferred upon reticulocyte membranes by the supernatant material was beta-adrenergic because it did not affect basal or fluoride-related activity and was completely inhibited by propranolol. Guanine nucleotides were present in the supernatant but could account for only a fraction of the total activity because the supernatant was able to cause greater stimulation than maximal concentrations of GTP and when specified concentrations of exogenous GTP were compared with equivalent nucleotide concentrations in the supernatant, the supernatant always led to greater activity. The supernatant was resolved into protein-and nucleotide-containing components by ion-exchange chromatography. Each component was approximately one-half as active in amplifying catecholamine-dependent adenylate cyclase as the unresolved, crude supernatant material. The activity eluted in the first peak of the DEAE chromatogram was resistant to alkaline phosphatase, sensitive to trypsin, not dialyzable and contained no detectable concentrations of GTP or GDP. In contrast, the activity eluted the second peak of the DEAE chromatogram was sensitive to alkaline phophatase, resistant to trypsin, completely dialyzable and contained both GTP (30 microM) and GDP (10 microM) in significant concentrations. Neither the crude supernatant nor its two active components affected the binding of [125I]-iodohydroxybenzylpindolol to reticulocyte membranes. These observations establish in rat reticulocytes the presence of protein and guanine nucleotide constituents which have independent influences upon the catecholamine-responsive adenylate cyclase of reticulocyte membranes.
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Modulation of adenylate cyclase in intact macrophages by microtubules. Opposing actions of colchicine and chemotactic factor. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)85785-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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McSwigan JD, Nicol SE, Gottesman II, Tuason VB, Frey WH. Effect of dopamine on activation of rat striatal adenylate cyclase by free Mg2+ and guanyl nucleotides. J Neurochem 1980; 34:594-601. [PMID: 7354334 DOI: 10.1111/j.1471-4159.1980.tb11185.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Naor Z, Catt K. Independent actions of gonadotropin releasing hormone upon cyclic GMP production and luteinizing hormone release. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)86174-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Anderson WB, Mukku VR, Johnson GS. Enhanced GTP-dependent activities of the adenylate cyclase system: basis for increased hormonal responsiveness. Arch Biochem Biophys 1979; 197:599-606. [PMID: 228602 DOI: 10.1016/0003-9861(79)90284-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Enhancement of hormonal stimulation in intact cells. Potentiation of GTP-dependent activation of adenylate cyclase. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(18)50450-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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