Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:4.6.1.1 (adenylate cyclase)
19,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

T cell activation requires two initial signals that first lead to the expression of interleukin 2 (IL 2) receptors and the initiation of IL 2 synthesis and then to T cell proliferation. Jurkat T lymphoma cells have been shown to be a good model for studying IL 2 synthesis because these cells also require two signals for activation. The first signal can be provided by the lectin phytohaemagglutinin (PHA), and the second one by the phorbol ester, 12-o-tetradecanoylphorbol 13-acetate (TPA). The regulation of IL 2 synthesis in Jurkat cells, however, is unclear, and the present study deals with the role of cAMP on IL 2 synthesis. In Jurkat cells, IL 2 synthesis appears to be highly regulated by the activity of adenylate cyclase. This was demonstrated by using different means to increase intracellular cAMP level, namely by using permeant cAMP analogs, using the activator of adenylate cyclase, forskolin, using the activator of the alpha subunit of the stimulatory GTP binding protein cholera toxin, and using inhibitors of phosphodiesterase. In addition, prostaglandins E1 and E2 were shown to bind specifically to Jurkat cells, to induce a rise in intracellular cAMP level, and to markedly decrease IL 2 synthesis. All together, these results suggest that in T lymphocytes, the prostaglandin E2 receptor is linked to adenylate cyclase through a GTP binding protein and regulates the production of IL 2 by controlling the intracellular cAMP level.
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PMID:Regulation of interleukin 2 synthesis by cAMP in human T cells. 303 99

The recently introduced frog olfactory cilia preparation (Chen and Lancet, 1984; Pace et al., 1985) has been useful for studies of molecular chemosensory mechanisms. Here we describe in detail the properties of this cilia preparation. The "calcium shock" procedure leads to a complete removal of the cilia from the olfactory epithelial surface. Isolated cilia constitute segments of proximal regions with 9 X 2 + 2 microtubular arrangement and a large proportion of membrane vesicles, probably derived from the ciliary distal segments. Polypeptides unique to the olfactory cilia preparation, compared to a control preparation of palate respiratory cilia, are identified by Coomassie brilliant blue staining, silver staining, and radiolabeled lectin overlays, as well as by biosynthetic labeling with 35S-methionine in epithelial explants and protein phosphorylation in isolated cilia. The olfactory cilia preparation contains odorant-sensitive adenylate cyclase, which is absent in control membranes from deciliated epithelium. High activities of tyrosine and serine/threonine protein kinases are also present. The olfactory cilia preparation described should be instrumental in the further elucidation of the biochemistry and molecular biology of vertebrate olfaction.
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PMID:Isolated frog olfactory cilia: a preparation of dendritic membranes from chemosensory neurons. 309 81

Rat renal papillary collecting duct (PCD) cells were isolated using collagenase and hyaluronidase digestion and a three-step low-speed centrifugation. As assessed by binding of the lectin Dolichos biflorus and determination of vasopressin-sensitive adenylate cyclase and Na+-K+-ATPase, the enrichment of PCD cells over a crude papillary cell preparation was 1.8, 2.4, and 1.4, respectively. Microscopic evaluation indicated that the preparation was greater than 90% pure PCD cells. The isolated cells were viable as evident from the high K/Na ratio of intracellular electrolytes measured by electron probe analysis (5.3), from the high ATP/ADP ratio (2.15), and the metabolic response to alterations in Na transport. Exposure to 2 mM ouabain or removal of Na reduced O2 consumption by 25-35%; the uncoupler carboxylcyanide-m-chlorophenylhydrazone more than doubled O2 consumption. In the presence of 14 mM glucose and at a PO2 of 100 Torr the cells produced substantial quantities of lactate. This aerobic glycolysis may account for greater than 20% of the ATP production. In the presence of rotenone, glycolysis increased by 56% and was able to maintain the cellular ATP level at 65% of control. In the absence of any exogenous substrate PCD cells respired normally and had a close to normal ATP content, but lactate production was markedly decreased. These results demonstrate that viable PCD cells can be isolated from rat kidney. At normal PO2 and in the presence of D-glucose the cells show a substantial amount of aerobic glycolysis, although their mitochondrial respiration is not rate limiting. In the absence of glucose the cells derive the majority of their energy from an as yet unidentified endogenous substrate.
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PMID:Purification of rat papillary collecting duct cells: functional and metabolic assessment. 330 74

The present study was performed to evaluate the different carbohydrate structure of rat LH isoelectric components related to their intrinsic biological activities. Terminal sialic acid residues were essential to the formation of multiple LH components observed in the isoelectric focussing profile, which was proved by their interaction with Ricinus communis agglutinin-120 following neuraminidase treatment, and the conversion of component F (pI, 10.0) to less alkaline components after incubation with liver Golgi membrane fraction in the presence of CMP-NeuNAc. The affinity studies using lentil lectin indicated that component F was not an asialo form of component A (pI 8.4). The serial removal of sialic acid residues from these components led to increases in the steroidogenic activity, owing to increases in the activation of the receptor-adenylate cyclase system. The enhancement of the steroidogenic activity by desialylation was very great in component A'(pI, 8.0) (751% increase), and decreased with increasing pI. It can be concluded that the different biological potencies of intact LH components are attributable principally to terminal sialic acid residues. However, the peripheral chains of asialo oligosaccharides of less alkaline components (pI, 8.0, 8.4) seem to prevent the maximal cellular responses, since their desialylated forms did not attain the maximum activity.
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PMID:Isoelectric properties, lectin binding characteristics and biological activities of neuraminidase-treated rat LH components. 338 29

A calmodulin-sensitive adenylate cyclase has been purified to apparent homogeneity from bovine cerebral cortex using calmodulin-Sepharose followed by forskolin-Sepharose and wheat germ agglutinin-Sepharose. The final product appeared as one major polypeptide of approximately 135,000 daltons on sodium dodecyl sulfate-polyacrylamide gels. This polypeptide was a major component of the protein purified through calmodulin-Sepharose. The catalytic subunit was stimulated 3-4-fold by calmodulin (CaM) with a turnover number greater than 1000 min-1 and was directly inhibited by adenosine. The catalytic subunit of the enzyme interacted directly with 125I-CaM on a sodium dodecyl sulfate-polyacrylamide gel overlay system, and this interaction was Ca2+ concentration dependent. In addition, the catalytic subunit was shown to directly bind 125I-labeled wheat germ agglutinin using a sodium dodecyl sulfate-polyacrylamide gel overlay technique, and N-acetylglucosamine inhibited binding of the lectin to the catalytic subunit. Calmodulin did not inhibit binding of wheat germ agglutinin to the catalytic subunit, and the binding of calmodulin was unaffected by wheat germ agglutinin. These data illustrate that the catalytic subunit of the calmodulin-sensitive adenylate cyclase is a glycoprotein which interacts directly with calmodulin and that adenosine can inhibit the enzyme without intervening receptors or G coupling proteins. It is concluded that the catalytic subunit of adenylate cyclase is a transmembrane protein with a domain accessible from the outer surface of the cell.
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PMID:Direct interaction between the catalytic subunit of the calmodulin-sensitive adenylate cyclase from bovine brain with 125I-labeled wheat germ agglutinin and 125I-labeled calmodulin. 366 98

Concanavalin A and wheat germ agglutinin are as effective as insulin in enhancing the rate of glucose transport and in inhibiting epinephrine-stimulated lipolysis in isolated adipocytes. These lectins, also like insulin, inhibit basal as well as epinephrine-stimulated adenylate cyclase activity of membranes obtained from homogenates of fat cells. Low concentrations of wheat germ agglutinin enhance the specific binding of insulin to receptors of fat cells and liver membranes. Higher concentrations of this plant lectin, as well as of concanavalin A, competitively displace the binding of insulin to receptors in these tissues. These effects are equally apparent in insulin-binding proteins solubilized from membranes, indicating that the plant lectins interact directly with insulin receptors. All of the effects observed with the plant lectins are reversed by simple sugars that bind specifically to these plant proteins. Agarose derivatives of the plant lectins effectively adsorb solubilized insulin-binding proteins, and these can be eluted with buffers containing specific simple sugars. The possible implications of these findings to certain biological properties (mitogenicity) of these lectins and to the mechanism of action of other growth-promoting substances are considered.
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PMID:Insulin-like activity of concanavalin A and wheat germ agglutinin--direct interactions with insulin receptors. 451 Feb 92

Human neutrophils were disrupted by brief sonication under conditions which preserve the hormone sensitivity of adenylate cyclase and yield minimal granule lysis. Fractions enriched in adenylate cyclase were analysed for hormonal and guanine nucleotide regulation of the enzyme as well as structural proteins. Adenylate cyclase was activated by PGE1 and isoproterenol in a GTP-dependent fashion, while f-met-leu-phe and C5a gave no stimulation. Cholera toxin treatment, which specifically modifies cyclase-related GTP-binding proteins, caused a dose-dependent enhancement of GTP activation, in which GTP alone activated maximally and PGE1 was without further effect. The following proteins were detected in the cyclase-containing vesicles: a 42 K mol. wt protein labeled selectively by cholera toxin; protein subunits observed in SDS gels at 214, 165, 105 and 47 K, of which the 47 K band was the most prominent and comigrated with actin; prominent lectin-binding activities at 165 K (concanavalin A and wheat germ agglutinin) as well as at 100 K (wheat germ agglutinin); and a set of proteins and lectin-binding activities in fractions containing beta-glucuronidase activity distinct from adenylate cyclase containing vesicles. The identification of receptor-controlled cyclase, GTP-binding regulatory proteins, cytoskeletal elements and unique lectin-binding activities in a single vesicle preparation should contribute to an understanding of receptor-mediated control of neutrophil function.
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PMID:Identification of receptor regulatory proteins, membrane glycoproteins, and functional characteristics of adenylate cyclase in vesicles derived from the human neutrophil. 608 23

A method is described for isolating preparative quantities of plasma membranes from sea urchin sperm. The final membrane fraction is homogeneous by sucrose density sedimentation and is enriched in adenylate cyclase as well as in the four glycoproteins accessible to radioiodination of intact sperm. The electrophoretic profiles of sperm membranes from three sea urchin species are very similar. The membrane preparation consists primarily of sealed vesicles which release carboxyfluorescein when exposed to detergents or distilled water. Ninety-two percent of the 125I-labeled vesicle material binds to wheat germ lectin columns, suggesting a right-side-out orientation. The isolated sperm membrane vesicles exhibit species specific adhesion to the surfaces of sea urchin eggs; this adhesion is blocked by pretreatment of the vesicles with trypsin or egg jelly. This method will be useful for isolating biologically active sperm membrane components involved in sperm-egg recognition during fertilization.
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PMID:Isolation and characterization of a plasma membrane fraction from sea urchin sperm exhibiting species specific recognition of the egg surface. 609 82

High voltage free flow electrophoresis has been applied to the separation of human platelet membranes. After short treatment with neuraminidase at the whole cell level, three membrane vesicle subpopulations have been isolated. Using a surface label (125I-labeled Lens culinaris lectin), the marker enzyme NADH-cytochrome c reductase, and lipid analysis, two of the fractions have been identified as of surface origin and the other consists of intracellular membrane elements. The distribution of adenylate cyclase, leucyl aminopeptidase, 5'-nucleotidase and Ca2+-ATPase has also been investigated, and their usefulness as markers for the different membrane fractions has been evaluated. All three fractions are vesicular but differ in size and character. Their phospholipid and cholesterol contents have been determined, and the cholesterol/phospholipid ratios of the two surface fractions are over twice that of the intracellular membrane, which also has a significantly lower microviscosity as determined by fluorescence polarization using diphenyl hexatriene. The polypeptide profiles from sodium dodecyl sulfate-polyacrylamide gel electrophoresis are particularly distinctive, with actin present in the two surface membrane fractions and absent from the intracellular membranes. Myosin, confirmed by its ATPase characteristics, is almost exclusively localized in one of the surface membrane fractions, and actin-binding protein is a prominent feature of the other.
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PMID:Characterization of human platelet surface and intracellular membranes isolated by free flow electrophoresis. 626 Jul 85

The guanine nucleotide regulatory protein component (N) of the frog erythrocyte membrane adenylate cyclase system appears to form a stable complex with the beta-adrenergic receptor (R) in the presence of agonist (H). This agonist-promoted ternary complex HRN can be solubilized with Lubrol. The guanine nucleotide regulatory protein associated with the solubilized complex can be adsorbed either to GTP-Sepharose directly or to wheat germ lectin-Sepharose via its interaction with the receptor which is a glycoprotein. Guanosine 5'-O-(3-thiotriphosphate)(GTP gamma S) can be used to elute the guanine nucleotide regulatory protein from either Sepharose derivative. The resulting N.GTP gamma S complex conveys nucleotide-dependent adenylate cyclase activity when combined with a Lubrol-solubilized extract of turkey erythrocyte membranes. The ability to observe GTP gamma S-dependent reconstitution of adenylate cyclase activity in the eluate from either resin required the formation of the HRN complex prior to solubilization. The N protein can be identified by its specific [32P]ADP ribosylation catalyzed by cholera toxin in the presence of [32P]NAD+. The existence of a stable HRN intermediate complex is supported by the observation that agonist pretreatment of frog erythrocyte membranes results in a 100% increase in the amount of 32P-labeled N protein eluted from the lectin-Sepharose in the presence of GTP gamma S compared to membranes pretreated with either antagonist or agonist plus GTP. Our results therefore provide evidence that the same guanine nucleotide-binding protein that associates with the beta-adrenergic receptor in the presence of agonist mediates adenylate cyclase activation.
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PMID:Evidence that a beta-adrenergic receptor-associated guanine nucleotide regulatory protein conveys guanosine 5'-O-(3-thiotriphosphate)- dependent adenylate cyclase activity. 626 49


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