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:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Urodilatin (CDD-/ANP-95-126), a new peptide hormone from human urine, is comprised of the same amino acid sequence as cardiodilatin (CDD-99-126/alpha-hANP) except for N-terminal extention by four amino acid residues. The presence of the recognition sequence Arg101-Arg-Ser-Ser104 for the cyclic AMP-dependent protein kinase enables rapid phosphorylation in the Ser104-position. Phosphorylation of urodilatin is associated with decreased vasorelaxant potency, while dephosphorylation of "phospho-urodilatin" by acidic phosphatase completely restores bioactivity.
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PMID:Phosphorylation and dephosphorylation of the natriuretic peptide urodilatin (CDD-/ANP-95-126) and the effect on biological activity. 252 51

Analysis by two-dimensional gel electrophoresis and Western blotting of the atrial natriuretic factor (ANF) content of atrial granules revealed the presence of at least 15 immunoreactive spots whose molecular mass distribution ranged from 16.8 to 35 kDa and their pI values from 5.12 to 5.98. About 90% of the immunoreactive ANF material was contained within four spots (spot 1: 34.8 kDa, pI 5.67; spot 5: 16.8 kDa, pI 5.50; spot 6: 16.8 kDa, pI 5.67; spot 7: 16.8 kDa, pI 5.98). Investigation of the molecular nature of spot 1 indicated that it is a dimer of pro-ANF since it possesses the same immunoreactivity, the same charge, double its mass, and can be converted with dithiothreitol into a 16.8-kDa pro-ANF form. Alkaline phosphatase and protein kinase A treatments indicated that spots 5, 6, and 7 are probably not phosphorylated forms of pro-ANF. Carboxypeptide A and B treatments in conjunction with amino acid analysis suggested that spot 7 is ANF-(1-128); spot 6, the major one, ANF-(1-126); and spot 5, ANF-(1-123) or ANF-(1-124). Water deprivation or morphine injection, two maneuvers which are known to influence ANF secretion and atrial ANF content, failed to affect the molecular heterogeneity of pro-ANF except for spot 1. The formation of the dimer appeared to be time-dependent. These results emphasize the heterogeneity of the pro-ANF molecule stored in atrial granules. We suggest that this heterogeneity may be due, in part, to the action of some proteases, such as carboxypeptidase E or a tripeptidyl carboxyhydrolase.
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PMID:Molecular heterogeneity of pro-atrial natriuretic factor. 253 Feb 24

Atrial natriuretic factor (ANF) is stored in atrial myocytes as a prohormone (ANF-(1-126] and is cosecretionally processed to the circulating ANF-related peptides, ANF-(1-98) and ANF-(99-126). Recently, we have shown that the cosecretional processing of ANF can be replicated in primary cultures of neonatal rat atrial myocytes maintained under serum-free conditions and that glucocorticoids are responsible for supporting this processing activity. Activators of protein kinase C (phorbol esters and alpha-adrenergic agonists) and of protein kinase A (cAMP analogs, forskolin, and beta-adrenergic agonists) were tested for their abilities to alter the rate of ANF secretion from the primary cultures. ANF secretion was stimulated approximately 4-fold after a 1-h incubation of the cultures with the phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA); maximal release occurred at about 100 nM TPA. Reversed-phase high performance liquid chromatography analysis of secreted material indicated that the cells efficiently cosecretionally processed ANF under both basal and TPA-stimulated conditions. However, incubating the cultures for more than 1 h with TPA resulted in a blunted secretory response to further TPA challenge and a 40-50% decrease in the quantity of ANF in the cells. The alpha-adrenergic receptor agonist phenylephrine was also capable of stimulating ANF secretion by about 4-fold at a half-maximal dose of about 1 microM. Phenylephrine-stimulated ANF secretion was inhibited by the alpha 1-adrenergic antagonist prazosin with half-maximal inhibition occurring at approximately 1 nM. Forskolin, 8-bromoadenosine 3':5'-cyclic monophosphate, and N6-2(1)-O-dibutyryladenosine 3':5'-cyclic monophosphate inhibited basal, TPA- and phenylephrine-stimulated ANF secretion. The beta-adrenergic agonist isoproterenol partially inhibited phenylephrine-stimulated ANF secretion with the maximal effect occurring at 1 nM. These results indicate that ANF secretion from the neonatal rat atrial cultures is enhanced by activators of protein kinase C, and decreased by activators of protein kinase A, and that these secretory effects may be mediated through the actions of alpha- and beta-adrenergic receptors, respectively.
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PMID:Regulation of atrial natriuretic factor-(99-126) secretion from neonatal rat primary atrial cultures by activators of protein kinases A and C. 254 6

We examined the effects of several in vitro experimental systems on the apparent potencies of putative secretagogues for stimulating ACTH release from rat anterior pituitary cells. Cells were prepared by trypsin digestion and gentle mechanical dispersion. Aliquots of the same cell preparations were tested in 1) a microperifusion system immediately after dispersion (day 0), 2) the same microperifusion system after 4 days of static suspension culture on a layer of Sephadex G-10 gel particles (day 4), 3) a static suspension system after 4 days of static suspension culture, and 4) a static monolayer system after 4 days of monolayer culture. Ovine CRF stimulated release of similar amounts of ACTH in all of the systems on days 0 and 4, except in one experiment, in which the response was less on day 4. Arginine vasopressin (AVP), oxytocin, and angiotensin II all appeared to be more potent in day 4 than in day 0 cells in the perifusion system, and the synergism of AVP with ovine CRF was also increased. Dioctanoylglycerol, which directly activates protein kinase-C, and forskolin, which directly activates adenylate cyclase, both stimulated greater release in day 4 cells. The mechanism(s) responsible for the difference in the responses of day 0 and day 4 cells is unknown. Epinephrine had only a small effect in the microperifusion system, but both epinephrine and norepinephrine had potencies comparable to AVP in the static suspension and monolayer systems. This was not due to prolonged exposure to the catecholamines, suggesting that these agents may act on other anterior pituitary cells to release metabolic products that secondarily stimulate the corticotrophs to release ACTH. The same situation appears to be true for atrial natriuretic factor. Gastrin-releasing peptide, its bioactive COOH-terminal half, which was active in a rat urinary bladder smooth muscle assay, its amphibian analog, bombesin, and cholecystokinin (26-33) were devoid of ACTH-releasing activity in all of the systems, in contrast to the findings of others. Since 4-day culture of dispersed cells improved most of their responses and diminished none, we postulate that they may more closely resemble normal pituitary cells in function, and since cellular metabolites are unlikely to accumulate in the interstitial fluid of the pituitary gland, we propose that the secretory functions of cells in perifusion systems may more closely resemble those in the pituitary gland in situ than they do in static incubation systems.
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PMID:Effects of several in vitro systems on the potencies of putative adrenocorticotropin secretagogues on rat anterior pituitary cells. 283 88

Atrial natriuretic factor (ANF) specifically stimulated the endogenous phosphorylation of a protein band in an isolated membrane fraction of human placenta. The apparent molecular weight of the substrate protein as determined by SDS-polyacrylamide gel electrophoresis is 160-170,000. In the same membrane fraction, ANF also stimulated guanylate cyclase activity in a dose-dependent manner. Guanosine 3':5'-cyclic monophosphate (cyclic GMP), added to the membrane fraction in lieu of ANF, also stimulated the phosphorylation of several protein bands, one of which have the same apparent molecular weight as the one stimulated by ANF. In contrast, adenosine 3':5'-cyclic monophosphate (cyclic AMP) at a similar concentration and hormones such as angiotensin II, insulin and vasopressin had no effect on the phosphorylation state of this protein band. The finding that ANF alters the phosphorylation state of a certain membrane protein and that this effect is mimicked by cyclic-GMP suggests that at least some of the biological action of ANF may be mediated by the phosphorylation of membrane protein involving a cyclic GMP-dependent protein kinase.
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PMID:Atrial natriuretic factor induced phosphorylation of human placental membrane protein: an effect mimicked by guanosine 3':5'-cyclic monophosphate. 287 3

Three classes of vasodilators mediate their effects through the activation of guanylate cyclase and the increased synthesis of cyclic GMP. Nitrovasodilators such as nitroglycerin, nitroprusside, hydroxylamine, azide, etc. result in the generation of the nitric oxide free radical that activates the cytosolic (soluble) isoenzyme form of guanylate cyclase. These agents have been useful in increasing cyclic GMP synthesis in numerous model systems and these effects are independent of extracellular calcium. The increased synthesis of cyclic GMP and the activation of cyclic GMP-dependent protein kinase result in the altered phosphorylation of many smooth muscle proteins including the dephosphorylation of myosin light chain, which is associated with vascular and tracheal smooth muscle relaxation. These latter effects may result from cyclic GMP decreasing cytosolic free calcium concentrations and the activity of myosin light chain kinase. Another class of vasodilators, designated endothelium-dependent vasodilators, includes a long list of agents such acetylcholine, histamine, A23187, ATP, thrombin, etc. that relax vessels only when the endothelium is intact. These agents result in the increased endothelial synthesis and/or release of a factor(s) designated endothelial-derived relaxant factor (EDRF), the structure of which is unknown. This labile factor also activates the soluble isoenzyme form of guanylate cyclase in the smooth muscle resulting in cyclic GMP accumulation and the same cascade of events as above. There is evidence that even under basal, non-stimulated conditions there is EDRF release that influences vascular tone due to the increased synthesis of cyclic GMP. A third class of vasodilators, atrial natriuretic factor (ANF) or atriopeptins, includes a family of peptides that are produced in cardiac atria and other tissues and influence cardiovascular volume and dynamics by causing natriuresis, diuresis, vasodilation and decreased renin, aldosterone and vasopressin secretion. These peptide hormones also increase cyclic GMP synthesis in vascular, renal, adrenal and other tissues. These effects are mediated through specific ANF receptors that couple to and activate the membrane (particulate) isoenzyme form of guanylate cyclase and increase cyclic GMP-dependent protein kinase activity. There are two ANF receptor subtypes in most cells and tissues that are 130,000 and 66,000 daltons. The ANF receptor of about 130,000 daltons, designated receptor ANF-R1 copurifies with particulate guanylate cyclase through numerous procedures and may be part of the membrane-associated guanylate cyclase complex.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Regulation and role of guanylate cyclase-cyclic GMP in vascular relaxation. 289 Jan 72

Vasopressin is actively involved in the regulation of blood pressure to the same degree as catecholamines and the renin angiotensin aldosterone system are, especially in stressful situations. Vasopressin induces and increase in blood pressure when mechanisms buffering its potent vasoconstrictor effect are altered. Vasopressin binds to specific membrane receptors classified into two main types. The V1 receptors found in blood vessels, platelets and hepatocytes are linked to two intra-cellular messengers, namely 1,2 diacylglycerol and 1,4,5 inositol triphosphate which stimulate protein kinase C and calcium-calmodulin kinase in the presence of calcium. V2-renal receptors stimulate the production of cyclic AMP which activates protein kinase A. Subsequently, the actin network is altered and particles containing pores agregate at the cell surface to produce water molecules reabsorption. Vasopressin modifies human hemostasis via platelet aggregation, stimulation of the three fractions of factor VIII, of factor XII and of fibrinopeptide A. These properties were used to treat hemostasis abnormalities seen in Von Willebrand's disease and hemophilia. There is a feed-back loop between vasopressin and the atrial natriuretic factor: vasopressin stimulates atrial natriuretic factor release via a V1 action whereas the atrial natriuretic factor reduces vasopressin release and inhibits vasopressin antidiuretic action.
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PMID:[Vasopressin, the antidiuretic hormone]. 295 73

Proatrial natriuretic factor (proANF) is phosphorylated in primary cultures of neonatal rat cardiocytes. Rittenhouse et al. (Rittenhouse, J., Moberly, L., O'Donnell, M. E., Owen, N. E., and Marcus, F. (1986) J. Biol. Chem. 261, 7607-7610) observed that cyclic AMP-dependent protein kinase phosphorylated synthetic peptides related to atrial natriuretic factor (ANF) and that phosphorylated ANF peptides were more effective in stimulating Na/K/Cl cotransport in smooth muscle cells than nonphosphorylated forms. In our studies, rat cardiocytes in culture were incubated with [32P]orthophosphoric acid, and ANF-related peptides in cell extracts and culture media were isolated using antisera to ANF. Both atrial and ventricular cardiocytes contained and secreted phosphorylated proANF, a 126-amino acid precursor of ANF. Phosphorylated and nonphosphorylated isoforms of proANF were resolved by isoelectric focusing; approximately 35% of the proANF secreted by cardiocytes was phosphorylated. proANF is phosphorylated on a serine residue localized to a 42-amino acid tryptic fragment (proANF residues 26-67). We conclude that proANF is phosphorylated by rat cardiocytes but not within the portion of the molecule destined to become ANF (proANF residues 99-126). Phosphorylation may have a role in the cellular mechanisms of proANF storage and secretion or in the modulation of potential biological activities of the circulating amino-terminal portion of proANF.
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PMID:Proatrial natriuretic factor is phosphorylated by rat cardiocytes in culture. 295 56

Synthetic atriopeptin II, an atrial natriuretic factor with potent vasodilatory effects, was studied in isolated strips of rat thoracic aorta to determine its actions on contractility, cyclic nucleotide concentrations and endogenous activity of cyclic nucleotide-dependent protein kinases. Atriopeptin II was found to relax aortic strips precontracted with 0.3 microM norepinephrine whether or not the endothelial layer was present. Relaxation to atriopeptin II was closely correlated in a time- and concentration-dependent manner with increases in cyclic GMP concentrations and activation of cyclic GMP-dependent protein kinase (cyclic GMP-kinase). The threshold concentration for all three effects was 1 nM. Atriopeptin II (10 nM for 10 min) produced an 80% relaxation, an 8-fold increase in cyclic GMP concentrations and a 2-fold increase in cyclic GMP-kinase activity ratios. Atriopeptin II did not significantly alter cyclic AMP concentrations or cyclic AMP-dependent protein kinase activity. These data suggest that cyclic GMP and cyclic GMP-kinase may mediate vascular relaxation to a new class of vasoactive agents, the atrial natriuretic factors. Similar effects have been observed with the nitrovasodilator, sodium nitroprusside, and the endothelium-dependent vasodilator, acetylcholine. Therefore, a common biochemical mechanism of action that includes cyclic GMP accumulation and activation of cyclic GMP-kinase may be involved in vascular relaxation to nitrovasodilators, endothelium-dependent vasodilators and atrial natriuretic factors.
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PMID:Atriopeptin II elevates cyclic GMP, activates cyclic GMP-dependent protein kinase and causes relaxation in rat thoracic aorta. 299 May 77

Control of the contraction/relaxation cycle in vascular smooth muscle is regulated by Ca2+ and the cyclic nucleotides, cAMP and cGMP. For the most part, the effectors of these intracellular messengers are the protein kinases. Four major protein kinases (myosin light chain kinase, protein kinase C, cAMP dependent protein kinase, and cGMP dependent protein kinase) have been identified in vascular smooth muscle. Substantial biochemical and physiological evidence exists supporting the involvement of Ca2+/calmodulin-mediated activation of myosin light chain kinase and phosphorylation of the 20,000 dalton P-light chain of myosin in the regulation of vascular contractile activity. However, alternative hypotheses exist which suggest that additional Ca2+ dependent regulatory mechanisms reside at other contractile protein sites. Calcium also activates protein kinase C, which requires phospholipid and diacylglycerol as co-factors instead of calmodulin. Protein kinase C also phosphorylates smooth muscle myosin P-light chain; however, phosphorylation occurs at a different site on the P-light chain and represses ATPase activity which has been stimulated by myosin light chain kinase-catalyzed phosphorylation. The precise physiological role of protein kinase C in modulating vascular smooth muscle contractile activity remains to be elucidated. Relaxation of vascular smooth muscle by some different relaxants is linked to either cAMP or cGMP formation. Correlative evidence also links activation of cAMP dependent protein kinase with relaxation. Two isozymes of cAMP dependent protein kinase exist in arterial smooth muscle; potential specific roles for each isozyme have not been elucidated. Mechanistically, relaxation mediated by both cyclic nucleotide-regulated protein kinases most likely involves primary effects on Ca2+ ion flux regulation rather than direct effects on contractile protein interactions. Activation of cGMP dependent protein kinase may be important in mediating the relaxant effects of endothelium derived relaxant factor or atrial natriuretic factor. Direct pharmacological modulation of smooth muscle vascular protein kinase activity represents an approach towards developing novel vasodilator agents. Various classes of agents, including phenothiazine antipsychotics, antidepressants, naphthalene sulfonamides, and certain lipophilic Ca2+ antagonists, inhibit myosin light chain kinase activity primarily by competition with the enzyme for Ca2+-calmodulin. However, additional inhibition via binding to the myosin P-light chain may also occur with some of these agents.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Regulation of contractile activity in vascular smooth muscle by protein kinases. 302 13


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