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)

Thyroxine control of cAMP-independent histone and casein phosphokinase activities was studied in thyroidectomized rats treated with thyroxine. All activities were evaluated in the presence of a thermostable inhibitor of cAMP-dependent enzymes. Cytosol enzymes can be resolved by sucrose gradient ultracentrifugation into three peaks of histone kinase activity (3.2S, 5S and 7.2S) and two peaks of casein kinases (3.6S and 7.1S). Neither thyroidectomy nor subsequent treatment of operated animals with thyroxine modifies the total histone kinase activity estimated, either in total cytosol or after its fractionation by the sucrose gradient ultracentrifugation. The activity ratios of different peaks were, however, changed. Casein kinase activity was significantly decreased after thyroidectomy (about 50%). Subsequent treatment with thyroxine restored this activity to its initial value. Sucrose gradient ultracentrifugation analysis showed that thyroxine action on the casein kinase activity is very specific. Only molecules that sediment in the 9S region were significantly stimulated by the hormone. Cortisol action on the casein kinase activity was studied in adrenalectomized animals treated with hormone for 24 h. Cortisol decreases the total casein kinase activity by about 30%. Sucrose gradient ultracentrifugation analysis showed that the population of molecules sedimenting at about 9S was the most sensitive to cortisol. The above data show that both thyroxine and cortisol control, in a selective way, the activities of cAMP-independent protein kinases. The same kinase molecules can be under double control by two different hormones that have opposite effects.
Mol Cell Endocrinol 1978 Dec
PMID:Hormonal regulation of cAMP-independent protein phosphokinase activities: thyroxine and cortisol control of enzymes from rat liver cytosol. 21 94

The role of cyclic AMP, if any, in the regulation of smooth muscle tone is not understood. In the present study the effects of cyclic AMP and of protein kinase on the uptake of calcium by "microsomal", "plasma" and "mitochondrial" preparations obtained from bovine tracheal smooth muscle were examined. Cyclic AMP and protein kinase had only a slight and variable effect on the uptake of calcium by microsomes, and no effect on the uptake of calcium by the plasma membrane or the mitochondria. These findings are not compatible with a role of cyclic AMP and protein kinase in the control of the uptake of calcium by the subcellular organelles of tracheal smooth muscle.
Arch Int Pharmacodyn Ther 1978 Dec
PMID:Effects of cyclic AMP and of protein kinase on the calcium uptake by various tracheal smooth muscle organelles. 21 9

The time course of TSH-dependent protein phosphorylation was studied in calf thyroid slices labeled in vitro with 32Pi. Several of the proteins identified by two-dimensional electrophoresis displayed striking increases in 32P labeling in the presence of TSH. Phosphorylation of histones H3 and H1 (two subgroups) was enhanced about 3.7-and 10-fold, respectively, after incubation with TSH (15 mu/ml) for 70 min. Histone phosphorylation showed a lag after exposure to TSH; a major increase occurred only after 30-min incubation but then increased progressively up to 2 h. The lag in histone phosphorylation was also observed with slices prelabeled with 32P before the addition of TSH. In contrast, phosphorylation of a minor basic protein, A5 was also increased by 15 mU/ml TSH but displayed different kinetics, increasing substantially at 10 min. This time course correlates well with the rise in intracellular cAMP levels and protein kinase activity in thyroid slices after TSH.
Endocrinology 1978 Dec
PMID:Time course of thyrotropin-dependent protein phosphorylation in thyroid slices. 21 8

The renal inner medulla is ordinarily exposed to osmolalities that are much higher and to O2 tensions that are lower than those in other tissues. The effects of media osmolality and O2 availability on basal and arginine vasopressin(AVP)-responsive soluble cyclic (c)AMP-dependent protein kinase activity were examined in slices of rat inner medulla. Increasing total media osmolality from 305 to 750 or 1,650 mosM by addition of urea plas NaCl to standard Krebs-Ringer bicarbonate buffer significantly reduced basal cAMP content and protein kinase activity ratios. This occurred in the presence or absence of O2. Incubation of slices in high osmolality buffer also blunted increases in inner medullary slice cAMP and protein kinase activity ratios induced by O2. These changes reflected predominantly an action of the urea rather than the NaCl content of high osmolality buffers. In contrast to effects on basal activity, high media osmolality significantly enhanced activation of inner medullary protein kinase by AVP. Conversely, increases in media O2 content suppressed AVP stimulation of enzyme activity. This inhibitory effect of O2 was best expressed at low osmolality. Naproxen and ibuprofen, inhibitors of prostaglandin biosynthesis, reduced basal kinase activity ratios and increased AVP responsiveness in the presence, but not in the absence, of O2. Exogenous prostaglandins (PG) modestly increased (PGE2 and PGE1) or did not change (PGF2alpha) cAMP and protein kinase activity ratios in O2-deprived inner medullary slices. Protein kinase activation by PGE2 was not observed in oxygenated inner medulla with high basal activity ratios. The stimulatory effects of PGE2 and PGE1 on protein kinase activity observed in O2-deprived slices were additive with those of submaximal or maximal AVP. PGE2, PGE1, and PGF2alpha all failed to suppress AVP activation of protein kinase. Thus, enhanced endogenous PGE production may contribute to the higher basal protein kinase activity ratios induced by O2. However, the results do not support a role for PGE2, PGE1, or PGF2alpha in O2-mediated inhibition of AVP responsiveness. The present data indicate that both solute content and O2 availability can alter the expression of AVP action on cAMP-dependent protein kinase activity in inner medulla. AVP activation of protein kinase is best expressed when osmolality is high and O2 availability is low, conditions that pertain in inner medulla during hydropenia.
J Clin Invest 1978 Dec
PMID:Effects of osmolality and oxygen availability on soluble cyclic AMP-dependent protein kinase activity of rat renal inner medulla. 21 25

Several methods were compared for estimating the amount of regulatory subunit of an 800-fold purified Type II cAMP-dependent protein kinase from bovine heart. These methods included a reversable binding assay using either cAMP, or 8-N3-[32P]cAMP, photoaffinity labeling with 8-N3-[32P]cAMP, and autophosphorylation of the regulatory subunit of the enzyme. Although the regulatory subunit had a slightly lower affinity for 8-N3-cAMP than for cAMP, the total amount of regulatory subunit could be determined by each of the procedures examined. The results indicate that the photoaffinity analog 8-N3-[32P]cAMP is able to label quantitatively all cAMP-binding sites of the regulatory subunit of this cAMP-dependent protein kinase.
J Cyclic Nucleotide Res 1978 Dec
PMID:Quantitative labeling of the regulatory subunit of type II cAMP-dependent protein kinase from bovine heart by a photoaffinity analog. 21 45

Cyclic AMP-dependent protein kinase from human erythrocyte plasma membranes was solubilized with Triton X-100, partially purified, and systematically characterized by a series of physicochemical studies. Sedimentation and gel filtration experiments showed that the 6.6 S holoenzyme had a Stokes radius (a) of 5.7 nm and was dissociated into native 4.8 S cAMP-binding (a = 4.5 nm) and 3.2 S catalytic (a = 2.6 nm) subunits. A minimum subunit molecular weight of 48,000 was established for the regulatory subunit by photoaffinity labeling with 8-azido[32P]cAMP, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and autoradiography. These data suggest an asymmetric tetrameric (R2C2) structure (Mr approximately equal to 160,000) for the membrane-derived enzyme. Membrane-derived protein kinase was characterized as a type I enzyme on the basis of its R subunit molecular weight, pI values (R, 4.9; holoenzyme, 5.75 and 5.95), dissociation by 0.5 M NaCl and 50 microgram/ml of protamine, 20-fold reduced affinity for cAMP in the presence of 0.3 mM MgATP, elution from DEAE-cellulose at low ionic strength, and kinetic and cAMP-binding properties. The physicochemical properties of the membrane protein kinase closely parallel the characteristics of erythrocyte cytosolic protein kinase I but are clearly dissimilar from those of the soluble type II enzyme. Moreover, regulatory subunits of the membrane-associated and cytosolic type I kinases were indistinguishable in size, shape, subunit molecular weight, charge, binding and reassociation properties, and peptide maps of the photoaffinity-labeled cAMP-binding site, suggesting a high degree of structural and functional homology in this pair of enzymes. In view of the predominant occurrence of particulate type II protein kinases in rabbit heart and bovine cerebral cortex, the present results suggest that the distribution of membrane-associated protein kinases may be tissue- or species-specific, but not isoenzyme-specific.
J Biol Chem 1979 Dec 25
PMID:Characterization and comparison of membrane-associated and cytosolic cAMP-dependent protein kinases. Studies on human erythrocyte protein kinases. 22 97

Deproteinized skeletal muscle extracts free of major nucleotides from control and insulin-treated rats were fractionated and assayed for inhibition of protein phosphorylation by cyclic adenosine monophosphate (AMP)-dependent and -independent protein kinases. A differential effect of insulin on a particular fraction was observed on cyclic AMP-dependent protein kinase but not on cyclic AMP-independent protein kinases. This fraction that inhibited cyclic AMP-dependent protein kinase also stimulated glycogen synthase phosphoprotein phosphatase. It is proposed that this fraction may contain a mediator substance generateed in the presence of insulin.
Science 1979 Dec 21
PMID:Generation by insulin of a chemical mediator that controls protein phosphorylation and dephosphorylation. 22 95

Two protein kinase activities have been separated from the supernatants of homogenized human blood platelets by DEAE cellulose chromatography. One of them (peak I enzyme) is an efficient stimulator of the uptake of Ca2+ into isolated membrane vesicles in the presence of cyclic AMP and ATP. The second (peak II enzyme), although equally active towards histone, exerts only about one third of the activity of the peak I enzyme. The stimulation of Ca2+ uptake is accompanied by the phosphorylation of a membrane protein with an apparent molecular weight of 22 000, which appears to play an essential role in the regulation of the intracellular Ca2+ level and hence of platelet activity.
Biochim Biophys Acta 1979 Dec 12
PMID:Regulation of the intracellular calcium level in human blood platelets: cyclic adenosine 3',5'-monophosphate dependent phosphorylation of a 22,000 dalton component in isolated Ca2+-accumulating vesicles. 22 23

Cyclic AMP-dependent protein kinases from several mammalian sources inhibit Na+-dependent alpha-aminoisobutyric acid transport by membrane vesicles isolated from 3T3 cells. Evidence is provided that phosphorylation of membrane proteins by the enzyme is responsible for the inhibition. Lysis of the vesicles, or a reduction in the intravesicular volume is not the cause of reduced transport. The cyclic AMP-dependent protein kinase and its catalytic subunit phosphorylate a number of membrane proteins. Most of these proteins are phosphorylated, but to a lesser extent in the absence of protein kinase or cyclic AMP. The phosphorylated proteins remain associated with the membranes during hypotonic lysis treatments, which would be expected to release intravesicular contents and loosely associated membrane proteins. 32P-labeled bands detected on sodium dodecyl sulfate polyacrylamide gels after phosphorylation of membranes by the catalytic subunit of the cyclic AMP-dependent kinase are eliminated by treatment with either pronase or 1 N NaOH, but not by ribonuclease nor by phospholipase C. The stability of the incorporated radioactivity to hot acid and hydroxylamine relative to hot base suggests that most of the 32P from [gamma-32P]ATP is incorporated into protein phosphomonoester linkages.
Biochim Biophys Acta 1979 Dec 11
PMID:Inhibition of alpha-aminoisobutyric acid transport in membrane vesicles from mouse fibroblasts after phosphorylation by cyclic AMP-dependent protein kinase. 22 60

Polyoma T antigen immunoprecipitates contain a protein kinase-like activity which preferentially phosphorylates material of 50-60,000 daltons molecular weight. Phosphorylation is not diminished in extracts of polyoma tsA mutant-infected cells shifted to the nonpermissive temperature late in infection, conditions which inactivate the large T antigen. Phosphorylation is reduced or absent in cells infected with polyoma host range nontransforming (hr-t) mutants, which have defective small and medium T antigens. The major acceptor of phosphate is not the heavy chain of immunoglobulin, but appears to be the polyoma medium T antigen. The large T antigen is also phosphorylated, but usually to a lower specific activity. In terms of acid and alkali sensitivity and electrophoretic and chromatographic mobility in one and two dimensions, the phosphorylated residue behaves identically to phosphotyrosine and differently than phosphorylated serine, threonine, lysine and histidine.
Cell 1979 Dec
PMID:An activity phosphorylating tyrosine in polyoma T antigen immunoprecipitates. 1505 79


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