Summary
The role of cytosolic components in the regulation of mouse pancreatic islet adenylate cyclase activity was studied. Addition of mouse islet cytosol (27000 g supernatant of mouse islet sonicate), devoid of adenylate cyclase activity itself, increased adenylate cyclase activity by 93±17% (n = 9) in the 27000 g total particulate fraction of mouse islets. Addition of GTP stimulated adenylate cyclase activity by 91±11% (n = 13) or to the same degree as cytosol. Like GTP, the substance causing the enhancing activity of the cytosol was found to be dialysable, resistant to heat, sensitive to charcoal treatment and alkaline phosphatase and insensitive to digestion with trypsin. However, in contrast to the stimulation by GTP, the stimulation by cytosol was not inhibited by guanosine 5′-0-(2-thiodiphosphate), and furthermore, the effects of cytosol and GTP were additive. Neither NAD nor phosphoenolpyruvate stimulated adenylate cyclase activity. The cytosolic factor did not confer sensitivity towards glucose, Ca2+ or Ca2+-calmodulin on adenylate cyclase. The results demonstrate that mouse pancreatic islets contain a phosphocompound (or several compounds) distinct from GTP and capable of markedly stimulating adenylate cyclase. The identity of the compound and its physiological significance remain to be established.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Ross EM, Gilman AG (1980) Biochemical properties of hormonesensitive adenylate cyclase. Ann Rev Biochem 49: 533–564
Gholamhosein OR, Gammon DE, Bilezikian JP (1980) Regulation of catecholamine-responsive adenylate cyclase activity in rat reticulocyte membranes by endogenous factors. General characteristics and resolution into protein and nucleotide components. Biochim Biophys Acta 629: 455–469
Egan JJ, Majeska RJ, Rodan GA (1980) Osteosarcoma cytosol factor promotes parathyroid hormone stimulation of adenylate cyclase independent of GTP. Biochim Biophys Acta 632: 483–496
Macneil S, Crawford A, Amirrasooli H, Johnson S, Pollock A, Ollis C, Tomlinson S (1980) Stimulation of hormone-responsive adenylate cyclase activity by a factor present in the cell cytosol. Biochem J 188: 393–400
Crawford A, Macneil S, Amirrasooli H, Tomlinson S (1980) Properties of a factor in cytosol that enhances hormone-stimulated adenylate cyclase activity. Biochem J 188:401–407
Doberska CA, Martin BR (1977) Activation of rat liver plasma membrane adenylate cyclase by a cytoplasmic protein factor. FEBS Lett 82: 273–277
Bonnafous J-C, Dornand J, Mani J-C (1979) Deactivation of lymphocyte adenylate cyclase by affinity chromatography on Con Asepharose. FEBS Lett 99: 152–156
Ofulue AF, Nijjar MS (1981) Calmodulin activation of rat lung adenylate cyclase is independent of the cytoplasmic factors modulating the enzyme. Biochem J 200: 475–480
Thams P, Capito K, Hedeskov CJ (1982) Differential effects of Ca2+-calmodulin on adenylate cyclase activity in mouse and rat pancreatic islets. Biochem J 206: 97–102
Coll-Garcia E, Gill JR (1969) Insulin release by isolated pancreatic islets of the mouse incubated in vitro. Diabetologia 5: 61–66
Groves WE, Davis FC, Milnec BH (1968) Spectrophotometric determination of microgram quantities of protein without nucleic acid interference. Anal Biochem 22: 195–210
Geisler A, Klysner R, Thams P, Christensen S (1977) A simple and inexpensive protein binding assay for cyclic AMP in biological materials. Acta Pharmacol Toxicol 40: 356–368
Eckstein F, Cassel D, Levkovitz H, Lowe M, Selinger Z (1979) Guanosine 5′-0-(2-thiodiphosphate). An inhibitor of adenylate cyclase stimulation by guanine nucleotides and fluoride. J Biol Chem 254: 9829–9834
Seamon KB, Daly JW (1982) Calmodulin stimulation of adenylate cyclase in rat brain membranes does not require GTP. Life Sci 30: 1457–1464
Moss J, Vaughan M (1978) Isolation of an avian erythrocyte protein possessing ADP-ribosyltransferase activity and capable of activating adenylate cyclase. Proc Natl Acad Sci USA 75:3621–3624
Capito K, Hedeskov CJ (1977) Effects of glucose, glucose metabolites, and calcium ions on adenylate cyclase activity in homogenates of mouse pancreatic islets. Biochem J 162: 569–573
Hedeskov CJ (1980) Mechanism of glucose-induced insulin secretion. Physiol Rev 60: 442–509
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Thams, P., Capito, K. & Hedeskov, C.J. Characteristics of an adenylate cyclase enhancing factor from mouse pancreatic islet cytosol. Diabetologia 26, 375–378 (1984). https://doi.org/10.1007/BF00266040
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00266040