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Govindarajan AG, Lindow SE. Size of bacterial ice-nucleation sites measured in situ by radiation inactivation analysis. Proc Natl Acad Sci U S A 2010; 85:1334-8. [PMID: 16593912 PMCID: PMC279765 DOI: 10.1073/pnas.85.5.1334] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Four bacterial species are known to catalyze ice formation at temperatures just below 0 degrees C. To better understand the relationship between the molecular structure of bacterial ice-nucleation site(s) and the quantitative and qualitative features of the ice-nucleation-active phenotype, we determined by gamma-radiation analysis the in situ size of ice-nucleation sites in strains of Pseudomonas syringae and Erwinia herbicola and in Escherichia coli HB101 carrying the plasmid pICE1.1 (containing a 4-kilobase DNA insert from P. syringae that confers ice-nucleation activity). Lyophilized cells of each bacterial strain were irradiated with a flux of gamma radiation from 0 to 10.2 Mrad (1 Mrad = 10(6) J/kg). Differential concentrations of active ice nuclei decreased as a first-order function of radiation dose in all strains as temperature was decreased from -2 degrees C to -14 degrees C in 1 degrees C intervals. Sizes of ice nuclei were calculated from the gamma-radiation flux at which 37% of initial ice nuclei active within each 1 degrees C temperature interval remained. The minimum mass of a functional ice nucleus, active only between -12 degrees C and -13 degrees C, was about 150 kDa for all strains. The size of ice nuclei increased logarithmically with increasing temperature from -12 degrees C to -2 degrees C, where the estimated nucleant mass was 19,000 kDa. The ice nucleant in these three bacterial species may represent an oligomeric structure, composed at least in part of an ice gene product that can self-associate to assume many possible sizes.
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Affiliation(s)
- A G Govindarajan
- Department of Plant Pathology, University of California, Berkeley, CA 94720
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2
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Rodbell M. Structure-function relationships in adenylate cyclase systems. CIBA FOUNDATION SYMPOSIUM 2008:3-21. [PMID: 6128188 DOI: 10.1002/9780470720721.ch2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Hormone-sensitive adenylate cyclase systems are composed of hormone-recognition units (R), a nucleotide-regulatory unit (N) for reaction with GTP and divalent cations, and the catalytic unit (C). From the reported sizes of purified R and N subunits and target analysis of functional sizes of these units, the functions of the components for the binding and actions of hormones and GTP require minimally dimers, homologous or heterologous. It is proposed that the catalytic unit exists in the membrane also as a dimer and that its transition to the active state with MgATP as substrate involves corresponding transitions in linked dimers of the hormone-recognition and nucleotide-regulatory units. It is postulated that hormones trigger the activation process by inducing in concert with GTP and divalent cations the appropriate dimer structure of the holoenzyme. In large aggregates of such structures, realignment of only a few occupied holoenzyme units may be sufficient to induce activation of the total aggregate enzyme. This theory serves to explain the synergistic actions of hormones, and how several hormones can activate a common enzyme. It also provides an explanation for 'spare' receptors, and for the efficacy of hormone action.
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Baragli A, Grieco ML, Trieu P, Villeneuve LR, Hébert TE. Heterodimers of adenylyl cyclases 2 and 5 show enhanced functional responses in the presence of Galpha s. Cell Signal 2007; 20:480-92. [PMID: 18164588 DOI: 10.1016/j.cellsig.2007.10.033] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Accepted: 10/30/2007] [Indexed: 12/22/2022]
Abstract
Recent studies have demonstrated that adenylyl cyclase isoforms can form both homo- and heterodimers and that this may be the basic functional unit of these enzymes (see Cooper, D.M.F. and Crossthwaite, A.J. (2006) Trends. Pharmacol. Sci. 8:426-431). Here, we show that adenylyl cyclases 2 and 5 can form a functional heterodimeric complex in HEK293 cells using a combination of BRET, confocal imaging, co-immunoprecipitation and assays of adenylyl cyclase activity. The AC2/5 complex is formed constitutively and is stable in the presence of receptor or forskolin stimulation. The complex formed by AC2/5 is also much more sensitive to the presence of Galpha(s) and forskolin than either of the parent AC isoforms themselves. Finally, we also show that this complex can be detected in native tissues as AC2 and AC5 were localized to the same structures in adult mouse ventricular myocytes and neonatal mouse cardiac fibroblasts and could be co-immunoprecipitated from lysates of mouse heart.
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Affiliation(s)
- Alessandra Baragli
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Quebec, Canada
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5
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Feldman RD, Gros R. New insights into the regulation of cAMP synthesis beyond GPCR/G protein activation: implications in cardiovascular regulation. Life Sci 2007; 81:267-71. [PMID: 17604058 DOI: 10.1016/j.lfs.2007.05.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2007] [Revised: 04/12/2007] [Accepted: 05/19/2007] [Indexed: 11/25/2022]
Abstract
Regulation of intracellular concentrations of cyclic AMP is one of the most ubiquitous mechanisms for regulating cellular functions. Further, the manner in which cAMP production is regulated via G proteins at the level of adenylyl cyclase activation has been studied extensively. This review focuses instead on the recently identified mechanisms and roles for regulation of adenylyl cyclase functions beyond G protein activation. These mechanisms include: a) the coupling of particular isoforms of adenylyl cyclase to function within a single cell type b) regulation of membrane trafficking of higher order enzyme aggregates and c) raf kinase-dependent phosphorylation and sensitization of adenylyl cyclases--an important pathway for crosstalk between tyrosine kinase signaling cascades with regulation of cAMP-mediated responses.
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Affiliation(s)
- Ross D Feldman
- Cell Biology and Vascular Biology Research Groups, Robarts Research Institute, London, Ontario, Canada.
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6
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Kempner ES. Molecular size determination of enzymes by radiation inactivation. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 61:107-47. [PMID: 3281417 DOI: 10.1002/9780470123072.ch3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- E S Kempner
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, Bethesda, Maryland 20892
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7
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Beauregard G, Maret A, Salvayre R, Potier M. The radiation inactivation method as a tool to study structure-function relationships in proteins. METHODS OF BIOCHEMICAL ANALYSIS 2006; 32:313-43. [PMID: 3553856 DOI: 10.1002/9780470110539.ch6] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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8
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Ding Q, Gros R, Chorazyczewski J, Ferguson SSG, Feldman RD. Isoform-Specific Regulation of Adenylyl Cyclase Function by Disruption of Membrane Trafficking. Mol Pharmacol 2004; 67:564-71. [PMID: 15547246 DOI: 10.1124/mol.104.006817] [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] Open
Abstract
Oligomerization plays an important role in endoplasmic reticulum processing and membrane insertion (and ultimately in regulation of function) of a number of transmembrane spanning proteins. Furthermore, it is known that adenylyl cyclases (ACs), critical regulators of cellular functions, associate into higher order (dimeric) forms. However, the importance of these higher order aggregates in regulating adenylyl cyclase activity or trafficking to the cell membrane is unclear. Therefore, we examined the potential role of oligomerization in the membrane trafficking of adenylyl cyclase. For this purpose, the ability of full-length adenylyl cyclase and various truncation mutants to self-assemble and to be targeted to the cell membrane was assessed. A truncation mutant comprised of the initial six transmembrane spanning domains and half of the C1 catalytic domain coimmunoprecipitated with full-length AC VI. Using both biotinylation assays and assessment of enzyme distribution using sucrose density gradients, we demonstrate that expression of this mutant in human embryonic kidney 293 cells impaired the ability of AC VI to traffic to the plasma membrane. Furthermore, mutant expression resulted in a significant reduction in adenylyl cyclase activity. The decrease in AC VI membrane expression was not caused by alterations in enzyme transcription. The effect of the mutant was specific for the AC V and VI isoforms and expression of the transmembrane M1 domain but not the C1a domain was required for the mutant to affect adenylyl cyclase activity. In aggregate, these data suggest that alterations in the ability of adenylyl cyclases to form higher order forms regulate both enzyme trafficking and enzyme activity.
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Affiliation(s)
- Qingming Ding
- Robarts Research Institute, 100 Perth Dr., London, ON, Canada N6A 5K8
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9
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Rodbell M. The role of GTP-binding proteins in signal transduction: from the sublimely simple to the conceptually complex. CURRENT TOPICS IN CELLULAR REGULATION 1992; 32:1-47. [PMID: 1318181 DOI: 10.1016/b978-0-12-152832-4.50003-3] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- M Rodbell
- Signal Transduction Section, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
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10
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Wong YH, Demoliou-Mason CD, Barnard EA. Opioid receptors in magnesium-digitonin-solubilized rat brain membranes are tightly coupled to a pertussis toxin-sensitive guanine nucleotide-binding protein. J Neurochem 1989; 52:999-1009. [PMID: 2538569 DOI: 10.1111/j.1471-4159.1989.tb01840.x] [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: 01/01/2023]
Abstract
Opioid receptors solubilized in Mg2+-digitonin (2%, wt/vol) from Mg2+-pretreated rat brain membranes maintain, in addition to high-affinity opioid agonist binding, the modulation by guanine nucleotides. One of the modes of expression of the latter property is an attenuation of agonist binding by guanine nucleotides in the presence of Na+. To investigate the molecular basis of this modulation and to identify the G protein(s) involved, the soluble receptors were [32P]ADP-ribosylated by means of Bordetella pertussis toxin and subjected to molecular size exclusion chromatography. In addition, soluble extracts were chromatographed on lectin and hydrophobic affinity columns. The binding of 35S- and 3H-labelled analogues of GTP was also monitored in the species separated. The oligomeric G protein-coupled opioid receptors and the guanine nucleotide/pertussis toxin-sensitive species showed similar chromatographic properties in all three systems. This indicates that the biochemically functional G protein-opioid receptor complex formed in Mg2+-pretreated membranes in the absence of an agonist is stable in digitonin solution and to chromatographic separation. Further analysis showed that the guanine nucleotide modulation of opioid receptors is via the pertussis toxin substrates with Mr of 41,000 and 39,000, which are identified as Gi and Go alpha subunits, respectively.
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Affiliation(s)
- Y H Wong
- MRC Molecular Neurobiology Unit, Medical Research Council Centre, Cambridge, England
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11
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Jass JR, Mukawa K, Goh HS, Love SB, Capellaro D. Clinical importance of DNA content in rectal cancer measured by flow cytometry. J Clin Pathol 1989; 42:254-9. [PMID: 2703541 PMCID: PMC1141864 DOI: 10.1136/jcp.42.3.254] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The DNA content of 369 rectal cancers was measured by flow cytometry. One hundred and four (28%) were diploid, 252 (68%) were aneuploid, and 13 (3.5%) were tetraploid. Diploid cancers were associated with an improved 5 year survival (p less than 0.001) and were more likely to present at an early stage. DNA content, however, did not confer independent prognostic information in a Cox model based on four discrete pathological variables. Patients were classified by a new system of prognostic grouping and those with a very good or a very poor outlook were removed leaving 137 prognostic group III patients. No further substratification of this group by DNA content or by four additional pathological variables could be achieved. As the new prognostic system is not improved by the addition of ploidy, routine adoption of flow cytometry in the assessment of rectal cancer cannot be recommended.
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Affiliation(s)
- J R Jass
- Department of Pathology, St Mark's Hospital, London
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12
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Sodium modulates opioid receptors through a membrane component different from G-proteins. Demonstration by target size analysis. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(19)81547-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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13
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Vessey D, Benfatto A, Kempner E. Bile acid: CoASH ligases from guinea pig and porcine liver microsomes. Purification and characterization. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)61196-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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14
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Cohen RM, McLellan C. The effects of glutaraldehyde cross-linking on the function of the adenylate cyclase complex of turkey erythrocytes. Life Sci 1986; 38:2151-61. [PMID: 3012235 DOI: 10.1016/0024-3205(86)90215-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Glutaraldehyde appears to preferentially effect the activation processes of the adenylate cyclase complex of turkey erythrocyte membranes. The primary effect of low concentration (0.01 percent, 0.05 percent, and 0.1 percent) glutaraldehyde membrane treatment is to decrease catecholamine-stimulated cAMP formation. The effect can be blocked by prior activation of the system with isoproterenol + p[NH]ppG. 0.6 percent glutaraldehyde treatment of membranes has substantial effects on both F(-)- and catecholamine-stimulated cAMP production. The effects are blocked by prior activation of the adenylate cyclase complex with NaF, but not by isoproterenol + p[NH]ppG. Glutaraldehyde at these concentrations has no effect on Mn++-stimulated cAMP formation. The data is discussed with respect to the organization of the major macromolecular components of the adenylate cyclase complex as it exists within the native membrane prior to and following activation of the system.
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15
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Verkman AS, Skorecki KL, Ausiello DA. Radiation inactivation of multimeric enzymes: application to subunit interactions of adenylate cyclase. THE AMERICAN JOURNAL OF PHYSIOLOGY 1986; 250:C103-14. [PMID: 3942201 DOI: 10.1152/ajpcell.1986.250.1.c103] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Radiation inactivation has been applied extensively to determine the molecular weight of soluble enzyme and receptor systems from the slope of a linear ln (activity) vs. dose curve. Complex nonlinear inactivation curves are predicted for multimeric enzyme systems, composed of distinct subunits in equilibrium with multimeric complexes. For the system A1 + A2----A1A2, with an active A1A2 complex (associative model), the ln (activity) vs. dose curve is linear for high dissociation constant, K. If a monomer, A1, has all the enzyme activity (dissociative model), the ln (activity) vs. dose curve has an activation hump at low radiation dose if the inactive subunit, A2, has a higher molecular weight than A1 and has upward concavity when A2 is smaller than A1. In general, a radiation inactivation model for a multistep mechanism for enzyme activation fulfills the characteristics of an associative or dissociative model if the reaction step forming active enzyme is an associative or dissociative reaction. Target theory gives the molecular weight of the active enzyme subunit or complex from the limiting slope of the ln (activity) vs. dose curve at high radiation dose. If energy transfer occurs among subunits in the multimer, the ln (activity) vs. dose curve is linear for a single active component and is concave upward for two or more active components. The use of radiation inactivation as a method to determine enzyme size and multimeric subunit assembly is discussed with specific application to the hormone-sensitive adenylate cyclase system. It is shown that the complex inactivation curves presented in the accompanying paper can be used select the best mechanism out of a series of seven proposed mechanisms for the activation of adenylate cyclase by hormone.
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16
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Lang MA, Preston AS, Handler JS, Forrest JN. Adenosine stimulates sodium transport in kidney A6 epithelia in culture. THE AMERICAN JOURNAL OF PHYSIOLOGY 1985; 249:C330-6. [PMID: 2994488 DOI: 10.1152/ajpcell.1985.249.3.c330] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The effects of adenosine receptor agonists and antagonists were examined in epithelia formed in culture by A6 cells, a continuous cell line derived from Xenopus laevis kidney. A6 epithelia have a high electrical resistance and a short-circuit current that is equal to net sodium flux from mucosal to serosal surface. Adenosine, 2-chloroadenosine, 5'-(N-ethyl)carboxamidoadenosine, and N6-(L-2-phenylisopropyl) adenosine produced concentration-dependent increases in short-circuit current. Stimulation of short-circuit current by 2-chloroadenosine occurred at concentrations of 0.05 microM and above, with half-maximal stimulation occurring at 0.3 microM. 5'-(N-ethyl)carboxamidoadenosine was more potent than N6-(L-2-phenylisopropyl)adenosine, the usual order of potency for activation of stimulatory adenosine receptors. Theophylline (100 microM), an adenosine receptor antagonist, reduced the short-circuit current response to adenosine and 2-chloroadenosine by 85-90%. Amiloride, an agent that inhibits both basal and adenosine 3',5'-cyclic monophosphate (cAMP)-stimulated short-circuit current in A6 epithelia, completely and reversibly inhibited short-circuit current stimulated by 2-chloroadenosine. Adenosine and 2-chloroadenosine stimulated adenylate cyclase activity in a crude membrane preparation from A6 cells. Stimulation by adenosine was blocked by adenosine deaminase. 2-Chloroadenosine increased cell cAMP accumulation in intact epithelia. The results provide evidence that adenosine and adenosine receptor agonists stimulate adenylate cyclase and active sodium transport in an epithelial cell line of renal origin.
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17
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Harmon JT, Jamieson GA. Thrombin binds to a high-affinity approximately 900 000-dalton site on human platelets. Biochemistry 1985; 24:58-64. [PMID: 2986677 DOI: 10.1021/bi00322a010] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The functional sizes of the binding sites for thrombin on human platelets and isolated membranes have been determined by the technique of radiation inactivation: similar results were obtained. Independent studies using different radiation doses (0, 3, and 48 Mrad) and different thrombin concentrations (10(-10), 10(-8), and 10(-6) M) confirmed the presence of three binding sites with functional sizes of 900 000, 30 000, and 4000 daltons. The binding site of lowest apparent size (4000 daltons) probably corresponds to what has been termed nonspecific binding since its dissociation constant (2900 nM) is well outside the physiological range. The site of intermediate size (30 000 daltons) is also probably not involved in platelet activation since its dissociation constant (11 nM) is also beyond the concentration range required for activation, although it may be involved in other aspects of platelet-thrombin interaction. The sites with the largest functional size are probably important in platelet function since their dissociation constant (0.3 nM) is in the range required for platelet activation. The functional size of these sites (900 000 daltons) suggests that the high-affinity site for thrombin binding to platelets may involve a multimolecular complex of membrane components.
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18
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Leigh PJ, Cramp WA, MacDermot J. Identification of the prostacyclin receptor by radiation inactivation. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(18)90764-7] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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19
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Characterization of the glucocorticoid receptor. Comparison of wild type and variant receptors. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(17)42921-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Agonist binding promotes a guanine nucleotide reversible increase in the apparent size of the bovine anterior pituitary dopamine receptors. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(17)43946-9] [Citation(s) in RCA: 78] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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21
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Molecular properties of the slow inward calcium channel. Molecular weight determinations by radiation inactivation and covalent affinity labeling. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(17)44673-4] [Citation(s) in RCA: 78] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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22
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Ferry DR, Goll A, Glossmann H. Putative calcium channel molecular weight determination by target size analysis. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 1983; 323:292-7. [PMID: 6314150 DOI: 10.1007/bf00512466] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The molecular weight of the putative calcium channel in guinea-pig brain membranes, labelled with [3H]-nimodipine, has been determined in situ by target size analysis. Irradiation of guinea-pig brain membranes at 153-173 K with 10 MeV electrons reduced the density of [3H]-nimodipine binding sites without affecting the equilibrium dissociation constant. The decay of the calcium channel blocker binding site density as a function of radiation dose fits to a monoexponential function. Application of the target size theory gives a molecular weight of 185,000. [3H]-Flunitrazepam labelled benzodiazepine receptor target size was measured as an internal control. The molecular weight of the benzodiazepine receptors was 76,000, which is in good agreement with published results.
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Pestka S, Kelder B, Familletti PC, Moschera JA, Crowl R, Kempner ES. Molecular weight of the functional unit of human leukocyte, fibroblast, and immune interferons. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(17)44554-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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24
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Lübbecke F, Ferry DR, Glossmann H, Sattler EL, Doell G. Radiation inactivation of alpha 1-adrenoceptors. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 1983; 323:96-100. [PMID: 6310418 DOI: 10.1007/bf00634255] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Radiation inactivation of alpha 1-adrenoceptors in rat cerebral cortex membranes has been performed with 10 MeV electrons from a linear accelerator at temperatures less than or equal to -100 degrees C. Alpha 1-adrenoceptor inactivation was monitored with [ 3H ]-prazosin and [( 125I ]-2-(beta-4-hydroxylphenyl)ethylaminomethyl)tetralone [( 125I ]-HEAT). Saturation analysis of irradiated membranes with both ligands indicated that a decrease in alpha-adrenoceptor density occurred with increasing radiation dose. The dissociation constants of [ 3H ]-prazosin and [ 125I ]-HEAT were not markedly changed by the irradiation. Application of the target volume theory gave molecular weights of 91,500 +/- 1,700 (S.D.) (D37: 19,6 +/- 0.36 Mrad) with [ 125I ]-HEAT as ligand, and 77,000 +/- 18,000 (S.D.) (D37: 23.3 +/- 4.6 Mrad) with [ 3H ]-prazosin, respectively, when an empirical temperature correction factor of 2.8 was used. [ 3H ]-flunitrazepam-labelled benzodiazepine receptor target size was used as an internal control. The molecular weight of the alpha 1-adrenoceptors, corrected for this internal control, was 85,000 +/- 1.600 [( 125I ]-HEAT) and 71,500 +/- 17,000 [( 3H ]-prazosin).
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25
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Garfinkel AS, Kempner ES, Ben-Zeev O, Nikazy J, James SJ, Schotz MC. Lipoprotein lipase: size of the functional unit determined by radiation inactivation. J Lipid Res 1983. [DOI: 10.1016/s0022-2275(20)37945-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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26
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Muscarinic cholinergic receptor structure. Receptor size, membrane orientation, and absence of major phylogenetic structural diversity. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(18)32502-x] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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27
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Fraser CM, Greguski R, Eddy B, Venter JC. Autoantibodies and monoclonal antibodies in the purification and molecular characterization of neurotransmitter receptors. J Cell Biochem 1983; 21:219-31. [PMID: 6313709 DOI: 10.1002/jcb.240210304] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The combination of immunological advances with membrane receptor research has promoted rapid progress in the molecular characterization of neurotransmitter receptor molecules. We have to date produced monoclonal antibodies to beta 1-, beta 2-, and alpha 1-adrenergic, D2-dopaminergic, and muscarinic receptors. In addition we have discovered that some allergic respiratory disease patients possess circulating autoantibodies to beta 2-adrenergic receptors. These antireceptor antibodies in conjunction with specific receptor affinity reagents have allowed us to isolate, purify, and begin to characterize alpha- and beta-adrenergic, dopaminergic, and muscarinic receptors. For example, immunoprecipitation of turkey erythrocyte beta 1 receptors with monoclonal antibodies yields a single polypeptide Mr 65--70 K. In contrast, purification of beta 2-adrenergic receptors using either autoantibodies or monoclonal antibodies yields a receptor species with a subunit of Mr 55--59 K. Autoantibodies to beta 2 receptors demonstrate a 50--100% homology among beta 2 receptors from humans to rats, whereas monoclonal antibody FV-104 recognizes a determinant in the ligand binding site of all beta 1 and beta 2 receptors tested to date. These data suggest that beta 1- and beta 2-adrenergic receptors may have evolved from a common ancestor, perhaps by gene duplication.
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Schlegel W. Structure-function relationships for hormone receptors and adenylate cyclase: the contribution of target size analysis. JOURNAL OF RECEPTOR RESEARCH 1983; 3:339-57. [PMID: 6304307 DOI: 10.3109/10799898309041946] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Target size analysis of radiation inactivation has been used to determine structural features of hormone receptors and adenylate cyclase. This method allows the determination of molecular sizes of components of enzyme- or receptor-systems in impure preparations and in intact membranes. Principles of application of target size analysis and basic concepts for interpretation are discussed. Reviewing both biochemical and target size data on insulin receptors and adenylate cyclase it is attempted to outline the potential and the limitations of this biophysical approach.
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Simon P, Swillens S, Dumont JE. Size determination of an equilibrium enzymic system by radiation inactivation: theoretical considerations. Biochem J 1982; 205:477-83. [PMID: 7150227 PMCID: PMC1158510 DOI: 10.1042/bj2050477] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Radiation inactivation of complex enzymic systems is currently used to determine the enzyme size and the molecular organization of the components in the system. We have simulated an equilibrium model describing the regulation of enzyme activity by association of the enzyme with a regulatory unit. It is assumed that, after irradiation, the system equilibrates before the enzyme activity is assayed. Our theoretical results show that the target-size analysis of these numerical data leads to a bad estimate of the enzyme size. Moreover, some implicit assumptions such as the transfer of radiation energy between non-covalently bound molecules should be verified before interpretation of target-size analysis. It is demonstrated that the apparent target size depends on the parameters of the system, namely the size and the concentration of the components, the equilibrium constant, the relative activities of free enzyme and enzymic complex, the existence of energy transfer, and the distribution of the components between free and bound forms during the irradiation.
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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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Allgayer H, Bachmann W, Hepp KD. Increased dose-response relationship of liver plasma membrane adenylate cyclase to glucagon stimulation in diabetic rats. A possible role of the guanyl nucleotide-binding regulatory protein. Diabetologia 1982; 22:464-7. [PMID: 6286396 DOI: 10.1007/bf00282591] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In view of controversial findings regarding the mechanism for the increased intracellular hepatic cyclic 3':5' adenosine monophosphate levels in diabetic rats, we studied the dose-response relationship of the adenylate cyclase to glucagon stimulation in severely diabetic and in diabetic, insulin-treated rats. An enhanced response to glucagon and an additional augmenting effect of guanosine triphosphate on hormonal stimulation of the adenylate cyclase activity were found in diabetes which were reversible with insulin treatment. The results suggest a role of the regulatory guanyl nucleotide-binding protein in diabetes leading to an increased dose response relationship of the hepatic adenylate cyclase system to glucagon.
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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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Pollet R, Kempner E, Standaert M, Haase B. Structure of the insulin receptor of the cultured human lymphoblastoid cell IM-9. Evidence suggesting that two subunits are required for insulin binding. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(19)68283-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Swillens S, Dumont JE. A pitfall in the interpretation of data on adenylate cyclase inactivation by irradiation. FEBS Lett 1981; 134:29-31. [PMID: 9222317 DOI: 10.1016/0014-5793(81)80543-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- S Swillens
- Institut de Recherche Interdisciplinaire, School of Medicine, Free University of Brussels, Belgium
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