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:4.6.1.2 (guanylate cyclase)
8,497 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Atrial natriuretic factor (ANF) receptors with and without guanylate cyclase activity were simultaneously purified to apparent homogeneity from bovine adrenal zona glomerulosa cell membrane fractions. The particulate guanylate cyclase which co-purified with the ANF receptor showed one of the highest specific activity reported. The receptors with or without the guanylate cyclase activity showed high affinities to ANF (99-126). The receptor without the cyclase showed a high affinity to truncated ANF analogs, ANF (103-123) and ANF (105-121), whereas the cyclase-linked receptor had a much lower affinity to these analogs. Both of the receptors migrated as a single band with a molecular weight of 135,000 daltons on SDS-gel electrophoresis under non-reducing conditions. The 135,000 daltons band of the receptor without the cyclase was shifted to a 62,000 daltons band under reducing conditions, but the band for the cyclase-linked receptor was not shifted. These results demonstrated the presence of two subtypes of ANF receptor in bovine adrenal cortex and indicate two different modes of intracellular action of ANF.
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PMID:Purification and characterization of two types of atrial natriuretic factor receptors from bovine adrenal cortex: guanylate cyclase-linked and cyclase-free receptors. 288 69

A novel method for isolation of cilia and ciliary membrane vesicles from Paramecium tetraurelia has been developed. Using a continuous Percoll gradient of low osmolarity after fragmentation of purified cilia by French Press treatment two membrane fractions with different buoyant densities were obtained. These fractions were further purified by conventional discontinuous sucrose density gradients and characterized biochemically and by electron microscopy. Guanylate cyclase, a membrane bound enzyme, was found almost exclusively in membrane vesicles of high buoyant density while the voltage-sensitive calcium-channel of the ciliary membrane was predominantly localized in low density vesicles. Examination of both fractions by SDS polyacrylamide gel electrophoresis revealed only minor differences in protein pattern in the 34 and 64 kilodaltons range. Morphologically both membrane vesicle fractions had a diameter of about 300 nm, however, the high density vesicle fraction contained a considerably larger amount of multilamellar structures with a multishell, onion-like appearance. Freeze-fracture analysis failed to detect differences in intramembrane particle content between low and high density vesicles. The possible biological relevance of the spatial separation of the calcium-sensor enzyme guanylate cyclase and the voltage-sensitive calcium-channels in the ciliary membrane is discussed in terms of a diffusion controlled mechanism for graded signal transmission.
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PMID:Differential distribution of voltage-dependent calcium channels and guanylate cyclase in the excitable ciliary membrane from Paramecium tetraurelia. 612 13

A comparative study of brain guanylate cyclase from different animal species (including man, bird, fish and amphibian) has been performed using a specific antibody directed against soluble rat brain guanylate cyclase. Analyses were performed on supernatant fractions by the double-immunodiffusion test, by the protein blotting technique after SDS-polyacrylamide gel electrophoresis and by analytical isoelectric focusing on agarose allowing specific immunodetection of isoelectric patterns. Membrane-bound guanylate cyclase from rat brain and soluble guanylate cyclase from several rat tissues cross-reacted with the antibody. All the brain enzymes tested were found to be identical by double-immunodiffusion. The electrophoretic and isoelectrophoretic profiles of the different brain guanylate cyclases were found to exhibit many common features with some differences between mammalian and non-mammalian enzymes. In human brain, guanylate cyclase has been localized in glial and neuronal cells by immunohistochemistry. The results demonstrate that guanylate cyclase has been well conserved during the course of evolution and are consistent with the involvement of guanylate cyclase and cyclic GMP in basic cellular function.
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PMID:Antigenic conservation of brain guanylate cyclase during evolution. 612 59

Two vertebrate photoreceptor-specific membrane guanylyl cyclases, RetGC-1 and RetGC-2, are activated by a soluble 24-kDa retinal protein, p24, in a Ca(2+)-sensitive manner (Dizhoor, A.M., Lowe, D.G., Olshevskaya, E.V., Laura, R.P., and Hurley, J.B. (1994) Neuron 12, 1345-1352; Lowe, D.G., Dizhoor, A.M., Liu, K., Gu, O., Laura, R., Lu, L., and Hurley, J.B. (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 5535-5539). The primary structure of bovine p24 has been derived from peptide sequencing and from its cDNA. p24 is a new EF-hand-type Ca(2+)-binding protein, related but not identical to another guanylyl cyclase-activating protein, GCAP (Palczewski, K., Subbaraya, I., Gorczyca, W.A., Helekar, B.S., Ruiz, C.C., Ohguro, H. Huang, J., Zhao, X., Crabb, J.W., Johnson, R.S., Walsh, K.A., Gray-Keller, M.P., Detwiler, P.B., and Baehr, W. (1994) Neuron 13, 395-404) and other members of the recovering family of Ca(2+)-binding proteins. Antibodies against a truncated fusion protein and against a p24-specific synthetic peptide specifically recognize retinal p24 on immunoblot. Both antibodies inhibit activation of photoreceptor membrane guanylyl cyclase by purified p24. p24 is found only in retina, and it copurifies with outer segment membranes. Immunocytochemical analysis shows that it is present in rod photoreceptor cells. An immobilized antibody column was used to purify p24 from a heat-treated retinal extract. Purified p24 appears on SDS-polyacrylamide gel electrophoresis as a homogeneous protein not contaminated with GCAP, and it activates photoreceptor guanylyl cyclase in vitro at submicromolar concentrations. Ca2+ inhibits this activation with an EC50 near 200 nM and a Hill coefficient of 1.7. Recombinant p24 expressed in 293 cells effectively stimulates photoreceptor guanylyl cyclase. These findings demonstrate that p24, like GCAP, imparts Ca2+ sensitivity to photoreceptor membrane guanylyl cyclase. We propose that p24 be referred to as GCAP-2 and that GCAP be referred to as GCAP-1.
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PMID:Cloning, sequencing, and expression of a 24-kDa Ca(2+)-binding protein activating photoreceptor guanylyl cyclase. 755 56

The human acrosome reaction (AR; sperm exocytosis) is absolutely required for fertilization. In the course of further characterizing the AR and its control, an AR-inhibiting glycoprotein (ARIG) from human seminal plasma was purified by differential centrifugation, carboxymethyl cellulose chromatography, chromatofocusing, and Sephacryl S300 gel filtration. A highly purified protein with a molecular weight of 74,000 was obtained as determined by gel filtration and SDS-PAGE. ARIG eluted in a narrow pH range (6.2-5.4) during chromatofocusing, corresponding to a pl of 5.8 +/- 0.4. It had covalent modifications, including internal disulfide bonds, and both complex N-linked and O-linked oligosaccharide chains. Lectin analysis suggested that sialic acid was absent and that the complex oligosaccharide chains had sequences containing galactose, galactosamine, and/or glucosamine in a beta 1-4 linkage. Mannose residues were also present. When ARIG was added to in vitro-capacitated human spermatozoa 30 min prior to the calcium ionophore A23187, the AR was significantly inhibited (ID50 = 8.5 micrograms/ml). In addition, ARIG reduced sperm exocytosis in response to atrial natriuretic peptide (a guanylate cyclase activator) and to the protein kinase C activators phorbol myristate acetate and dioctanoylglycerol. The ability of ARIG to block the human AR induced by a variety of agonists and the fact that biological activity of the protein was lost after removal of its sugar moieties suggests that it may function as a general inhibitor of sperm exocytosis and that its interaction with spermatozoa may be mediated by carbohydrate-binding proteins on the sperm cell.
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PMID:Purification and partial characterization of acrosome reaction inhibiting glycoprotein from human seminal plasma. 766 49

Specific binding of iodinated natriuretic peptides 125I-ANP and 125I-CNP was examined in the gill of the Atlantic hagfish Myxine glutinosa by tissue section autoradiography, saturation and competition analysis of binding to membrane preparations, affinity cross-linking, followed by SDS-PAGE and guanylate cyclase assays. Autoradiographs showed specific, saturable binding on the respiratory lamellar epithelium. In vitro analysis of the binding sites demonstrated that 125I-ANP bound to two receptor sites with the same affinity (Kd = 15.4 +/- 1.6 pmol l-1; Bmax = 45.9 +/- 3.0 fmol mg-1 protein). 125I-CNP bound to high- and low-affinity receptor sites; variables for the high-affinity site (Kd = 12.9 +/- 4.7 pmol l-1; Bmax = 23.4 +/- 6.5 fmol mg-1 protein) did not differ from those for the 125I-ANP sites. The low-affinity site had an apparent Kd and Bmax of 380 +/- 80 pmol l-1 and 120 +/- 21 fmol mg-1 protein, respectively. All receptors had an apparent molecular mass of approximately 150 kDa, with no indication of a mammalian type NPR-C at a lower apparent molecular mass. 1 nmol l-1 unlabelled rANP and 20 and 30 nmol l-1 unlabelled pCNP and C-ANF, respectively, competed for 50% of 125I-ANP sites. 0.1 nmol l-1 rANP and pCNP and 8 nmol l-1 C-ANF competitively inhibited 50% of 125I-CNP binding. Both rANP and pCNP stimulated cyclic GMP production, although rANP was a more potent stimulator than was pCNP. C-ANF did not stimulate cyclic GMP production. These data suggest the existence of an ANP guanylate-cyclase-linked receptor similar to the mammalian NPR-A and an ANP/CNP receptor that may be similar to, although not structurally homologous with, the mammalian NPR-C clearance receptor.
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PMID:Localisation and characteristics of natriuretic peptide receptors in the gills of the Atlantic hagfish Myxine glutinosa (Agnatha). 789 Oct 31

Photoaffinity labeling of atrial natriuretic factor (ANF) receptor in the plasma membranes from bovine aortic smooth muscle tissue using N alpha 5-(4-azidobenzoyl)-ANF-(5-28)- peptide labeled with 125I yielded a 130-kDa band. However, when smooth muscle cells from the same bovine aorta were placed in culture, the 130-kDa receptor quickly disappeared and a 60-kDa band began to appear at high density. After three passages, essentially no 130-kDa band was found and only the 60-kDa band was strongly labeled. The primary structures of the two receptor forms were compared by radiochemical peptide mapping after endoproteinase Glu-C digestion of photoaffinity-labeled and detergent-solubilized 130-kDa receptor from the aorta or the 60-kDa receptor from the cultured cells. The peptide mapping showed courses of digestion that were significantly different from each other, suggesting difference in their primary structures. The basal guanylate cyclase activity in the aortic membranes was 1.0 pmol cGMP produced.min-1.mg protein-1 at 37 degrees C using Mn(2+)-GTP as substrate. The corresponding activity in the membranes from the cultured cells was 20 fmol cGMP.min-1.mg protein-1. Binding studies gave a density of binding sites (Bmax) of 82 fmol/mg protein for the aortic membranes and 850 fmol/mg protein for the cultured cell membranes. These data suggest that the major form of ANF receptor in the cultured cells, namely the 60-kDa receptor, lacked guanylate cyclase activity. Northern blot analysis of poly(A)-RNA extracted form bovine thoracic aorta or adrenal cortex gave a single 3.6-kb band when 32P-labeled human A-type ANF receptor cDNA was used as a hybridization probe. However, no band was detected when C-receptor cDNA was used as a probe. In addition to the major 130-kDa band, extended SDS/PAGE revealed two additional faint bands with estimated molecular masses of 126 kDa and 135 kDa. Treatment with endoglycosidase H resulted in disappearance of the 126-kDa band and appearance of a 100-kDa band. The 130-kDa and 135-kDa bands were unchanged. Treatment by endoglycosidase F or glycopeptidase F reduced all three bands to a single 100-kDa band. These results suggest that the slight difference in mobility is due to different states of glycosylation.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Aortic smooth muscle contains guanylate-cyclase-coupled 130-kDa atrial natriuretic factor receptor as predominant receptor form. Spontaneous switching to 60-kDa C-receptor upon cell culturing. 790 Oct 5

We studied the activation and inactivation of recombinant guanylyl cyclase (GC) C stably expressed in human kidney 293 cells. Activation of GC-C by heat-stable enterotoxin (STa), Cd2+, hemin, or the detergent Triton X-100 was followed by a rapid inactivation of the enzyme. Adenine nucleotides were found to prevent the inactivation process in native membranes, as well as following enzyme solubilization and immunopurification. Inactivation of GC-C was not associated with dephosphorylation. However, the phosphorylation of GC-C was promoted by phorbol esters, known activators of protein kinase C. The activation of purified GC-C by STa required the presence of a nonspecific factor as exemplified by bovine serum albumin. When immunopurified GC-C, stabilized by ATP and bovine serum albumin, was analyzed by SDS-polyacrylamide gel electrophoresis under nonreducing conditions, proteins with almost twice the molecular mass (220 and 245 kDa) of the monomer were observed. The mobility of these high M(r) GC-C forms was reduced by STa, suggesting that STa induces a conformation change in a preexisting GC-C dimer. These results indicate that ATP interacts directly with GC-C, stabilizing its active conformation and that the activation of GC-C may occur in the absence of other specific regulatory factors.
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PMID:Heat-stable enterotoxin activation of immunopurified guanylyl cyclase C. Modulation by adenine nucleotides. 810 20

The membrane-bound guanylyl cyclase in vertebrate photoreceptor cells is one of the key enzymes in visual transduction. It is highly sensitive to the free calcium concentration ([Ca2+]). The activation process is cooperative and mediated by a novel calcium-binding protein named GCAP (guanylyl cyclase-activating protein). We isolated GCAP from bovine rod outer segments, determined amino acid sequences of proteolytically obtained peptides, and cloned its gene. The Ca2+-bound form of native GCAP has an apparent molecular mass of 20.5 kDa and the Ca2+-free form of 25 kDa as determined by SDS-polyacrylamide gel electrophoresis. Recombinant GCAP was functionally expressed in Escherichia coli. Activation of guanylyl cyclase in vertebrate photoreceptor cells by native acylated GCAP was half-maximal at 100 nM free [Ca2+] with a Hill coefficient of 2.5. Activation by recombinant nonacylated GCAP showed a lower degree of cooperativity (n = 2.0), and half-maximal activation was shifted to 261 nM free [Ca2+]. Immunocytochemically we localized GCAP only in rod and cone cells of a bovine retina.
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PMID:Functional characterization of a guanylyl cyclase-activating protein from vertebrate rods. Cloning, heterologous expression, and localization. 862 84

To characterize Ser1029 in STaR at a consensus sequence of phosphorylation site by PKC, two mutants of mS1029A with replacement of Ser1029 to Ala1029 and C delta 1029 lacking 22 amino acids including Ser1029 were prepared. Preincubation of the wild type-STaR (wt-STaR) transfectant with 1 microM PMA caused additional STa-mediated guanylyl cyclase (GC) activation compared to control, whereas the mS1029A- and C delta 1029-transfected cells did not show a similar enhanced GC activation by PMA. After metabolic labeling with [32P]phosphate, transfected cells with wt-STaR and mutants were incubated with 1 microM PMA. Subsequent 32P-radiolabeled proteins were immunoprecipitated using anti-STaR antibody, and analyzed by autoradiography after separation on SDS-PAGE. The immunoprecipitated wt-STaR but not mS1029A and C delta 1029 had a significant radioactivity. These results suggest that the effect of PMA on wt-STaR transfectants may be caused by phosphorylation of Ser1029. The C delta 1012 mutant, with further truncation (Gln1012-Phe1050) of the carboxy terminus, did not show STa-mediated GC activation. Based on these data, these 17 amino acids (Gln1012-Ala1028), essential for signaling of GC activation by STa, have an abundance of basic amino acids which might be functionally influenced by phosphorylation of Ser1029.
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PMID:The significance of Ser1029 of the heat-stable enterotoxin receptor (STaR): relation of STa-mediated guanylyl cyclase activation and signaling by phorbol myristate acetate. 879 7


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