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)

A number of 2-substituted cyclic nucleotide derivatives were synthesized and investigated as activators of cAMP-dependent protein kinase and as substrates for and inhibitors of cAMP phosphodiesterase. Ring closure of 5-amino-1-beta-D-ribofuranosylimidazol-4-carboxamide cyclic 3',5'-phosphate (1) with various aldehydes according to a new procedure (Meyer, R. B., Jr., Shuman, D.A., and Robins, R. K. (1974), J. Am. Chem. Soc. 96, 4962) gave new derivatives of adenosine cyclic 3',5'-phosphate with the following 2-substituents: n-propyl, n-hexl, n-octyl, n-decyl, styryl, o-methoxyphenyl, and 2-thienyl. Alkylation of 2-mercaptoadenosine cyclic 3',5'-phosphate (20, Meyer et al., 1974) gave new cAMP derivatives with the following 2-substituent: ethylthio, n-propylthio, isopropylthio, allylthio, n-decylthio, and benzylthio. Deamination of 2-methyl-,2-n-butyl-, and 2-ethylthioadenosine cyclic 3',5'-phosphate. Using multiple regression analysis, a striking relationship was found between the relative potency of the compounds as activators of bovine brain cAMP-dependent protein kinase and parameters describing the hydrophobic, steric, and electronic character of the substituents on these compounds. All compounds were substrates for a cyclic nucleotide phosphodiesterase preparation from rabbit kidney. Additionally, the compounds were as a group, good inhibitors of the hydrolysis of cAMP by phosphodiesterase preparations from rabbit lung, beef heart, and dog heart.
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PMID:2-substituted derivatives of adenosine and inosine cyclic 3',5'-phosphate. Synthesis, enzymic activity, and analysis of the structural requirements of the binding locale of the 2-substituent on bovine brain protein kinase. 16 24

Canine cardiac sarcoplasmic reticulum vesicles contain intrinsic protein phosphatase activity, which can dephosphorylate phospholamban and regulate calcium transport. This phosphatase has been suggested to be a mixture of both type 1 and type 2 enzymes (E. G. Kranias and J. Di Salvo, 1986, J. Biol. Chem. 261, 10,029-10,032). In the present study the sarcoplasmic reticulum phosphatase activity was solubilized with n-octyl-beta-D-glucopyranoside and purified by sequential chromatography on DEAE-Sephacel, polylysine-agarose, heparin-agarose, and DEAE-Sephadex. A single peak of phosphatase activity was eluted from each column and it was coincident for both phospholamban and phosphorylase a, used as substrates. The partially purified phosphatase could dephosphorylate the sites on phospholamban phosphorylated by either cAMP-dependent or calcium-calmodulin-dependent protein kinase(s). Enzymatic activity was inhibited by inhibitor-2 and by okadaic acid (I50 = 10-20 nM), using either phosphorylase a or phospholamban as substrates. The sensitivity of the phosphatase to inhibitor-2 or okadaic acid was similar for the two sites on phospholamban, phosphorylated by the cAMP-dependent and the calcium-calmodulin-dependent protein kinases. Phospholamban phosphatase activity was enhanced (40%) by Mg2+ or Mn2+ (3 mM) while Ca2+ (0.1-10 microM) had no effect. These characteristics suggest that the phosphatase associated with cardiac sarcoplasmic reticulum is a type 1 enzyme, and this activity may participate in the regulation of Ca2+ transport through dephosphorylation of phospholamban in cardiac muscle.
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PMID:The phospholamban phosphatase associated with cardiac sarcoplasmic reticulum is a type 1 enzyme. 130 82

Prior studies indicate that cAMP-dependent protein kinase (PKA) and calcium calmodulin-dependent multifunctional protein kinase II (CaM-KII) inhibit Na(+)-H+ exchanger as assayed in octyl glucoside solubilized rabbit renal brush border membrane proteins reconstituted into artificial lipid vesicles. An anion exchange chromatography fraction of these proteins which elutes between 0.2 and 0.4 M NaCl (Fraction B), however, fails to demonstrate regulation of the transporter by PKA. The present studies examine regulation of the Na(+)-H+ exchanger by CaM-KII using Fraction B proteins. As compared to the initial total protein extract, Fraction B demonstrated increased Na(+)-H+ exchange activity. CaM-KII inhibited the Na(+)-H+ exchanger in Fraction B by 38.2 +/- 10.6% in an ATP and calmodulin-dependent manner. The results of the present studies suggest that CaM-KII-mediated inhibition of the Na(+)-H+ exchanger involves the phosphorylation of different polypeptides than those mediating the inhibition of this transporter by PKA.
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PMID:Regulation of the renal Na(+)-H+ exchanger by calcium calmodulin-dependent multifunctional protein kinase II. 132 33

This study examines the hypothesis that interferon-gamma (IFN-gamma) induces protein phosphorylation as part of the signal transduction pathway used to activate U937 cells. U937 cells labeled with 32Pi were treated with IFN-gamma, proteins were separated by two-dimensional polyacrylamide gel electrophoresis, and the pattern of protein phosphorylation was determined by autoradiography and computer-assisted two-dimensional densitometry. IFN-gamma (100 U/ml) induced phosphorylation of multiple proteins between 15 and 60 min, and the proteins were all dephosphorylated by 120 min. The pattern of proteins phosphorylated in the presence of ionomycin or PMA differed from that of IFN-gamma. Inhibition of protein kinase C activity by 1-(5-isoquinolinesulfonyl)2-methyl piperazine (H-7), inhibition of calcium-calmodulin-dependent protein kinase by N-(6-aminohexyl)-5-chloro-naphthalenesulfonamide (W-7), and inhibition of calcium redistribution by 8-(diethylamino)-octyl 3,4,5-trimethoxybenzoate hydrochloride (TMB-8) did not inhibit the majority of IFN-gamma-induced protein phosphorylation. These data indicate that IFN-gamma induces protein phosphorylation in U937 cells by activation of a kinase different from, or in addition to, protein kinase C or calcium-calmodulin-dependent kinase.
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PMID:Interferon-gamma induces phosphorylation of multiple small-molecular-weight proteins in U937 cells. 133 Dec 58

Rat submandibular and parotid gland exocytosis is primarily controlled by beta-adrenergic receptor stimulation. Although its precise role in the regulation of salivary gland exocytosis is not fully understood, protein phosphorylation, mediated by the activation of cAMP-dependent protein kinase, may be directly involved. Previous studies suggest that analogous 26-kDa integral membrane phosphoproteins may play a direct role in regulating exocytosis. Studies were here undertaken to purify and partially characterize both phosphoproteins. After endogenous phosphorylation with 32P, subcellular fraction and solubilization of the microsomal fraction in n-octyl beta-glucopyranoside, the 26-kDa integral membrane phosphoproteins were purified by high performance liquid chromatography (HPLC), followed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and electroelution of the proteins. Amino acid analysis indicated a significant number of serine amino acids: N-terminal sequence data demonstrated a high level of homology; and trypsin digestion followed by reversed-phase HPLC indicated the possibility of multiple phosphorylation sites.
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PMID:Purification and partial characterization of analogous 26-kDa rat submandibular and parotid gland integral membrane phosphoproteins that may have a role in exocytosis. 152 94

Whole-cell recordings were performed at isolated crypts from the distal colon of the rat. Enterocytes in intact crypts, patched from the basolateral side, exhibited a gradient in the resting zero-current potential. Along the axis of the crypt, the highest potentials were measured in the ground region, the lowest in the surface region. The cholinergic agonist, carbachol, induced a hyperpolarization and an increase of the outward current in both the middle and the ground cells of intact crypts. This effect could be prevented by Ba2+ or by the intracellular Ca2+ antagonist, 8-(N, N-diethylamino)-octyl-3,4,5-trimethoxy-benzoate hydrochloride (TMB-8). Its action, however, was not dependent on the presence of external Ca2+. Both ground cells and the cells in the middle part of the crypt responded to forskolin, an activator of the adenylate cyclase, with a depolarization. In the middle part of the crypt, the depolarization induced by forskolin was associated with an increase of the outward current. It could be blocked by the Cl- channel blocker, 5-nitro-2-(3-phenylpropylamino)-benzoate, indicating an increase of Cl- conductance. In contrast, the forskolin-induced depolarization in the ground part of the crypt was associated with a decrease of the outward current. This effect could be prevented by Ba2+, indicating a decrease of a potassium conductance. The changes in outward current could be prevented by the presence of an inhibitor of protein kinase A in the pipette solution. In conclusion, these results suggest that carbachol, an agonist acting on the Ca2+ pathway, indirectly causes Cl- secretion by an increase of the driving force, i.e. the membrane potential. Only the activation of cyclic AMP synthesis by forskolin is able to increase Cl- conductance in the rat colon. The latter response seems to be dependent on the state of differentiation of the enterocytes.
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PMID:Calcium- and cyclic-AMP-mediated secretory responses in isolated colonic crypts. 166 Jan 28

The possible involvement of protein kinase C and Ca2+ metabolism in the proteolytic enzyme release from schistosome cercariae was studied. Cercariae were placed in dechlorinated tap water containing 0.37 mM calcium in the small glass petri dish and exposed to the stimuli (linoleic acid, phorbol esters, and Ca2+ ionophore) with or without inhibitors of protein kinase C or Ca2+ metabolism. The proteolytic activity of incubation medium of cercariae thus treated was measured by the azocoll assay. The penetration response of cercariae induced by linoleic acid, a physiological stimulus, was mimicked by phorbol esters. When exposed to phorbol esters, 0.02 to 2 microM of 12-O-tetradecanoylphorbol-13-acetate (TPA) and 0.2 to 2 microM of phorbol-12,13-dibutyrate (PDBu), cercariae ceased the swimming movement, began a rhythmic thrusting of the anterior tip of the parasite, and released the proteolytic enzyme, but they did not shed the tails. Lowering Ca2+ in water by addition of 5 mM ethylene glycol-bis(beta-aminoethyl ether) N,N,N',N'-tetraacetic acid (EGTA), phorbol ester-induced release of enzyme was completely inhibited. Phorbol ester-induced release of enzyme was partially inhibited by 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7), an inhibitor of protein kinase C, at a concentration of 100 microM. H-7 alone, at a concentration of 100 microM, did not affect the swimming movement of cercariae. The cercariae were stimulated to release the enzyme by high concentrations (10 and 100 microM) of the Ca2+ ionophore, A23187, but enzyme was not released by low concentrations (0.5 and 1 microM) of this drug. Cercariae exposed to A23187 behaved differently from those exposed to phorbol esters. They ceased swimming, showed strong muscle contraction, and shed their tail. A23187 stimulated cercariae to release the enzyme in the water containing 5 mM EGTA. A23187-induced enzyme release was not inhibited by N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7), a calmodulin antagonist, trifluoperazine (TFP), a better calmodulin antagonist on schistosome, or by verapamil, a Ca2+ channel blocker. Linoleic acid-induced release of enzyme was partially inhibited by 0.5 and 5 mM of EGTA and by 1 to 100 microM of H-7. While it was not inhibited by N-[2-(methylamino)ethyl]-5-isoquinolinesulfonamide (H-8) and N-(2-guanidinoethyl)-5-isoquinolinesulfonamide (HA-1004), inhibitors of cyclic nucleotide-dependent protein kinase which were used as negative controls of H-7, W-7, TFP, 8-(N,N-diethylamino)octyl 3,4,5-trimethoxybenzoate (TMB-8), an intracellular Ca2+ antagonist, and verapamil.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Schistosoma mansoni: possible involvement of protein kinase C in linoleic acid-induced proteolytic enzyme release from cercariae. 201 70

Previous in vitro studies with detergent-solubilized rabbit renal brush-border membrane (BBM) proteins have suggested that adenosine 3',5'-cyclic monophosphate (cAMP)-dependent protein kinase A (PKA)-mediated inhibition of the Na(+)-H+ exchanger requires the presence of 42-kDa cofactor that is distinct from the exchanger itself. We sought to determine whether there was a protein in native rabbit renal BBM vesicles that has characteristics similar to that of the 42-kDa cofactor. Incubation of native BBM vesicle proteins with a hypotonic phosphorylation solution containing purified catalytic subunit of PKA resulted in phosphorylation of a number of BBM proteins, including a protein with an apparent molecular weight that was similar but not identical to that of the 42-kDa cofactor obtained from anion-exchange column chromatography of n-octyl glucoside-extracted BBM proteins. The identity between the BBM vesicle protein and the 42-kDa cofactor was established by phosphopeptide maps and radioiodinated peptide maps. These results indicate that native BBM vesicles contain a number of proteins that are phosphorylated by PKA when the PKA and ATP are present inside the vesicle space. One of these proteins appears to be identical to the 42-kDa protein that, as previously suggested by in vitro studies, acts as a regulatory cofactor mediating the inhibitory effect of PKA on the renal Na(+)-H+ exchanger.
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PMID:Identification of a putative Na(+)-H+ exchanger regulatory cofactor in rabbit renal BBM. 217 60

The structure of phospholamban, a 30-kDa oligomeric protein integral to cardiac sarcoplasmic reticulum, was probed using ultraviolet absorbance and circular dichroism spectroscopy. Purified phospholamban was examined in three detergents: octyl glucoside, n-dodecyloctaethylene glycol monoether (C12E8) and sodium dodecyl sulfate (SDS). Ultraviolet absorption spectra of phospholamban reflected its aromatic amino acid content: absorption peaks at 275-277 nm and 253, 259, 265 and 268 nm were attributed to phospholamban's one tyrosine and two phenylalanines, respectively. Phospholamban phosphorylated at serine 16 by the catalytic subunit of cAMP-dependent protein kinase exhibited no absorbance changes when examined in C12E8 or SDS. Circular dichroism spectroscopy at 250-190 nm demonstrated that phospholamban possesses a very high content of alpha-helix in all three detergents and is unusually resistant to denaturation. Dissociation of phospholamban subunits by boiling in SDS increased the helical content, suggesting that the highly ordered structure is not dependent upon oligomeric interactions. The purified COOH-terminal tryptic fragment of phospholamban, containing residues 26-52 and comprising the hydrophobic, putative membrane-spanning domain, also exhibited a circular dichroism spectrum characteristic of alpha-helix. Circular dichroism spectra of phosphorylated and dephosphorylated phospholamban were very similar, indicating that phosphorylation does not alter phospholamban secondary structure significantly. The results are consistent with a two-domain model of phospholamban in which each domain contains a helix and phosphorylation may act to rotate one domain relative to the other.
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PMID:Secondary structure of detergent-solubilized phospholamban, a phosphorylatable, oligomeric protein of cardiac sarcoplasmic reticulum. 252 65

Legionella micdadei, a pathogen which enters into host phagocyte phagolysosomal structures, contains at least two protein kinases. We have purified to homogeneity the predominant, nucleotide-independent protein kinase and examined its ability to catalyze the transfer of phosphate from ATP to acceptors in human neutrophils. The L. micdadei protein kinase catalyzed the phosphorylation of proteins of 11.5, 14, 19, 23, 28, 34, and 38 kilodaltons (kDa) present in a Triton X-100 extract of neutrophil membranes and of 11.5, 13.5, 25, and 38 kDa in the neutrophil cytosol. Tubulin was a good substrate for the L. micdadei protein kinase in vitro. The bacterial kinase also catalyzed the phosphorylation of phosphatidylinositol (PI) at about half the rate at which histones were phosphorylated; phosphatidylinositol-4-phosphate (PIP) was not phosphorylated by the kinase. The PI kinase activity of the L. micdadei enzyme was optimum at pH 7.0, and the divalent cation requirement was satisfied best by Mg2+ and Ca2+. The maximum rate of PI phosphorylation was obtained with 0.6 mM PI; in the presence of MgCl2 (10 mM), the Km for PI was 0.9 mM and the Km for ATP was 1.5 mM. The detergents octyl-beta-D-glucoside (10 to 20 mM) and Triton X-100 (0.5%) stimulated kinase activity twofold when PI was the phosphate acceptor; however, only octyl glucoside stimulated histone kinase activity. Various membrane phospholipids inhibited PI kinase activity. The most potent phospholipid inhibitor was the product of the PI kinase reaction, PIP, which at a 0.6 mM concentration inhibited both PI and tubulin phosphorylation by 80%. The inhibition of kinase activity by PIP when histone served as the acceptor was noncompetitive in character. The L. micdadei kinase also phosphorylated PI in intact. (3H)inositol-labeled neutrophils. The PI kinase and histone kinase activities of teh L. micdadei kinase copurified and cofucused (pI, 5.8) when subjected to isoelectric focusing, suggesting that the two enzymatic activities reside in a single protein.
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PMID:Legionella micdadei protein kinase catalyzes phosphorylation of tubulin and phosphatidylinositol. 254 13


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