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

---

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

The regulation patterns of gastric acid secretion in rats were investigated. Pentagastrin and histamine stimulate gastric acid secretion, but the inhibitors of DNA-dependent synthesis of RNA and of proteins prevent only the pentagastrin action. It has been found that pentagastrin induces histidine decarboxylase in gastric mucosa, ensuring local accumulation of histamine. The latter activates adenylate cyclase and results in 3',5'-AMP accumulation in gastric tissues. The administration of pentagastrin, histamine or 3',5'-AMP enhances the activity of gastric carbonic anhydrase, the enzyme which takes part in HCl formation. The data suggest that these three compounds act sequentially (pentagastrin leads to histamine leads to3',5'-AMP) and the effect of the last one could be mediated through 3',5'-AMP dependent protein kinase. The experiments in vitro demonstrated that gastric carbonic anhydrase can be separated into two isoenzymes and thephosphorylation of one of them by the 3',5'-AMP dependent protein kinase sharply increases its activity. The findings raise the possibility that histamine and 3',5'-AMP, mediating gastrin action, form together with enzymes (histidine decarboxylase, adenylate cyclase, protein kinase, carbonic anhydrase) a caascade of amplifiers. Autoradiographic studies have shown that [3H]-pentagastrin is not bound by oxyntic cells but adheres preferentially to histamine-producing alpha-like endocrine cells and to the chief cells, while 3H-histamine adheres preferentially to oxyntic and to chief cells. Electron microscopy indicates that only pentagastrin (but not histamine) initiates in alpha-like endocrine cells ultrastructural changes characteristic for induction. Pentagastrin, histamine and 3',5'-AMP administration produces in oxyntic cells ultrastructural changes typical for the secretion processes. These results lead to assumption that pentagastrin (gastrin) induces histidine decarboxylase in alpha-like endocrine cells of gastric glands. Histamine which is secreted enhances adenylate cyclase activity in the neighbouring oxyntic cells where 3',5'-AMP dependent protein kinase activates carbonic anhydrase by means of phosphorylation. These different cells form, probably, a multicellular functional unit for gastric acid secretion.
...
PMID:Integration of biochemical functions of different cells of rat gastric mucosa for hydrochloric acid secretion. 18 10

Properties and partial purification of the bovine adrenal cholesterol esterase from the 100000 X g supernatant fraction were investigated. Variations of the enzyme activity with time-dependent (enzymatic) and time-dependent (non enzymatic) effects have been demonstrated. Mg2 has been proved to inhibit the enzyme activity by a non-enzymatic effect in 50mM Tris/HCl buffer, pH 7.4. A time-dependent inactivation of the cholesterol esterase has been observed in the same buffer. The enzyme could be protected from this enzymatic inactivation by its substrate, cholesterol oleate. cAMP, ATP and Mg2 cuase a time-dependent stimulation of the enzyme in 50mM Tris/HCl buffer, pH 7.4. This result suggests that corticotropin activates the soluble cholesterol esterase from bovine adrenals via cAMP-dependent protein kinase. This view is strengthened by the incorporation of 32P radioactivity from [gamma-32P] ATP into the protein fraction of the 100,000 X g supernatant. The protein-bound 32P radioactivity could be co-purified with the enzyme activity during the partial purification of the soluble cholesterol esterase.
...
PMID:In vitro activation of a soluble cholesterol esterase from bovine adrenals by a cAMP-dependent protein kinase. 18 77

Rat kidney plasma membranes prepared by the method of FITZPATRICK et al. (J Biol. Chem. 244, 3561, 1969) show protein kinase activity as well as specific cAMP binding activity (diss. const. 1.3 x 10-9 M). However, no stimulation of kinase activity by cAMP is observed in presence of exogenous substrates (e.g. histone) and only poor stimulation with endogenous substrates in the membrane could be shown. At high ionic strength (1 M NaCl) cAMP independent protein kinase activity can be solubilized. Low ionic strength buffer (1 mM Tris-HCl pH 7.4 1 mM EDTA) and non-ionic detergents (Lubrol PX, Lubrol WX and Triton X 100) are able to solubilize both protein kinase activity and cAMP binding activity. Protein kinase activity seemed to be only loosely associated with the membrane, whereas cAMP binding protein appears to be more firmly fixed into the membrane structure. In addition we have found that membranes serve as a good substrate for cytosol protein kinase (s) and Ca-ion concentration influences the effect of cAMP on protein kinase activity. Dependent on the increase of Ca-ion concentration the effect of cAMP on protein kinase changes from activation to inhibition.
...
PMID:Some aspects of rat kidney plasma membrane cAMP-receptor and its connection with protein kinase activity. 18 76

The cyclic AMP-dependent protein kinase catalyzes the phosphorylation of hydroxyproline present in the heptapeptide, Leu-Arg-Arg-Ala-Hyp-Leu-Gly. The Km value for the reaction with this substrate was high (approximately 18 mM) compared to the Km values reported for the analogous threonine and serine-containing peptides, which were 0.59 mM and 0.016 mM, respectively (Kemp, B.E., Graves, D.J., Benjamini, E., and Krebs, E.G. (1977) J. Biol. Chem. 252, 4888-4894). The Vmax value with the hydroxyproline-containing peptide was 1 mumol . min-1 mg-1 in contrast to Vmax values of 6 mumol . min-1 mg-1 and 20 mumol . min-1 mg-1 for the threonine- and serine-containing peptides, respectively. Phosphate esterified to hydroxyproline present in the peptide was relatively stable in hot alkali, only 10% being released as Pi within 30 min in 0.1 N NaOH at 100 degrees C, whereas all of the phosphate was released from the phosphoserine peptide analogue under these conditions. Phosphohydroxyproline in the peptide was also more stable to acid (5.7 N HCl, 110 degrees C) than phosphoserine, the time for 50% release as Pi being 15 h in contrast to 6 h for the latter.
...
PMID:Phosphorylation of hydroxyproline in a synthetic peptide catalyzed by cyclic AMP-dependent protein kinase. 22 52

A 60-kDa substrate of calmodulin-dependent protein kinase in rabbit "heavy" skeletal sarcoplasmic reticulum (SR) was characterized by purification and cDNA cloning. Purification was achieved by column chromatography using DEAE-Sephacel, heparin-agarose, and hydroxylapatite in 0.5% 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonic acid (CHAPS). Analyses of amino acid sequence and composition indicated that the CHAPS-soluble 60-kDa protein is an isoform of phosphoglucomutase (PGM). cDNAs encoding two isoforms of PGM were isolated from rabbit skeletal muscles. The translated amino acid sequences show that the isoforms, PGM1 and PGM2, differ in the N-terminal 77 amino acids and that PGM2 is identical to the 60-kDa protein in the SR. Northern blot analysis showed that the size of the mRNA encoding PGM2 is 2.4 kilobases. The PGM enzyme activity was markedly inhibited in SR membranes, while perturbation of the membranes with CHAPS or guanidine-HCl recovered the enzyme activity. KCl (0.15-1 M) led to a partial recovery of the enzyme activity suggesting that the charge interaction is not the primary force for PGM-SR interaction. PGM is localized in the heavy fraction of SR, where calsequestrin and Ca2+ release channel are enriched. Our results demonstrate that an isoform of PGM localized in junctional skeletal SR is the 60-kDa substrate of calmodulin-dependent protein kinase.
...
PMID:Purification, characterization, and molecular cloning of a 60-kDa phosphoprotein in rabbit skeletal sarcoplasmic reticulum which is an isoform of phosphoglucomutase. 132 21

In the process of protein kinase reaction carried out in the mixture consisting of tris-HCl buffer, EDTA, MgCl2, gamma-32P-ATP and the cytoplasmic fraction of rabbit pulmonary cells the phosphorylation of proteins with molecular weights of 150 and 55 kD took place. The addition of L. pneumophila culture fluid to the reaction mixture resulted in the splitting of phosphorylated proteins with the formation of the component having a molecular weight of 45 kD. These disturbances in protein kinase reaction were found to occur due to the involvement of Legionella cytoplasm, a previously characterized protein with a molecular weight of 37 kD, into the process. In this connection, the participation of cytolysin in the pathogenesis of Legionella infection may also be considered from the viewpoint of the effect produced by cytolysin on the regulatory processes affecting the metabolism of target cells.
...
PMID:[The splitting of the acceptor proteins of the protein kinase system in eukaryotic cells by Legionella cytolysin]. 195 Feb 77

Stimulation of the gastric parietal cell requires massive membrane transformations as H(+)-pumps from the domain of cytoplasmic tubulovesicles are recruited into the apical plasma membrane domain. The recycling of membrane pools, through fusion and fission processes that accompany stimulation and inhibition of HCl secretion, also involves highly selective events of protein incorporation and segregation. This manuscript describes several proteins that have been identified with the apical plasma membrane from maximally stimulated parietal cells, and broadly characterizes them either as permanent resident proteins of the apical membrane, or transient proteins that move into and out of the apical membrane as the cell progresses through the secretory cycle. A typical example of transient association with the apical membrane concerns the pump proteins, including the 94 kDa catalytic alpha-subunit of the H+K(+)-ATPase and its newly discovered beta-subunit glycoprotein, which move between tubulovesicles. Proteins that remain associated with the apical plasma membrane during rest and secretion include actin, and an 80-kDa phosphoprotein, which has been variously called 80 K, ezrin, p81 and cytovillin, and whose phosphorylation is increased by the histamine/cAMP pathway of parietal cell stimulation. An example of a cytosolic protein that becomes associated with the apical plasma membrane after stimulation is a 120-kDa protein, which appears to have protein kinase activity. Note that the identification, localization and characterization of the K+ and Cl- transport proteins, which participate in net HCl secretion, are of immediate importance.
...
PMID:Membrane and protein recycling associated with gastric HCl secretion. 216 24

Responsiveness of gonadotropes to GnRH depends, in part, on the number of plasma membrane GnRH receptors. Since the steady state level of these plasma membrane receptors is a function of the rates of both receptor generation (synthesis, unmasking, and recycling) and loss (internalization, degradation, and inactivation) we have sought to quantify the rate of synthesis of GnRH receptors in pituitary cell cultures. Further, since the protein kinase-C activator phorbol 12-myristate 13-acetate (PMA) has been shown to unmask a class of GnRH receptors that appear to be uncoupled from phosphoinositide turnover, we have measured the rate of synthesis of this second receptor population. The present studies use the density shift technique; incorporation of densely labeled amino acids confers a higher density to newly synthesized proteins and allows their separation by physical means. Cultures of pituitary cells were prepared from female weanling rats. After cells had attached to the culture dishes, medium was replaced at 12-h intervals with medium containing either densely labeled or normal amino acids. After the incubation, GnRH receptors were covalently linked to a photoaffinity receptor agonist [( 125I]Tyr5-[azido-benzoyl-D-Lys6-GnRH]), then solubilized with 1+ sodium dodecyl sulfate. In some cultures PMA (50 nM) was included during the photoaffinity agonist-binding step. Newly synthesized (dense) receptors were separated from previously synthesized receptors by velocity sedimentation (0-20% sucrose in 1% sodium dodecyl sulfate-10 mM Tris-HCl, pH 7.0; centrifuged at 156,000 x g for 24 h). Gradients were fractionated, and the radioactivity contained in each fraction was quantified. Newly synthesized GnRH receptors exhibited a higher density, as evidenced by further migration into the gradient, than did normal GnRH receptors. There was a delay of approximately 6 h between exposure to dense amino acids and the appearance of densely labeled GnRH receptors at the plasma membrane. Equilibrium for incorporation of dense amino acids into GnRH receptors was 48 h of exposure to dense amino acids. The time required for synthesis of half the entire population of GnRH receptors was 28 +/- 2 h (mean +/- SEM; n = 4). Scatchard analysis and the pattern of GnRH-stimulated LH release from densely labeled cells indicated that they bound the photoaffinity label (Kd = 0.4 nM; approximately 1 fmol receptor/microgram DNA) and secreted gonadotropin normally. Additionally, treatment with PMA caused a significant increase (181 +/- 24%) in photoaffinity agonist binding, consistent with previous observations.
...
PMID:Synthesis of gonadotropin-releasing hormone receptors by gonadotrope cell cultures: both preexisting receptors and those unmasked by protein kinase-C activators show a similar synthetic rate. 254 92

A procedure for detecting protein kinase activities of the alpha and beta subunits of calmodulin-dependent protein kinase II separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis is described. After electrophoresis, the gel was immersed in 6 M guanidine HCl for 1 h and then in a buffer containing 0.04% Tween 40 for 16 h at 4 degrees C for renaturation of the resolved polypeptides. The renatured polypeptides in the gel were incubated with [gamma-32P]ATP for phosphorylation of either the substrate included in the polyacrylamide gel or the kinase itself. After removal of the unreacted [gamma-32P]ATP, the protein kinase activities were visualized by autoradiography. Two radioactive protein bands of Mr 50,000 and 60,000, which corresponded to the alpha and beta subunits, were detected only when the phosphorylation was carried out in the presence of Ca2+ and calmodulin. Approximately 0.05 micrograms of the enzyme could be detected on a gel containing no protein substrate. When microtubule-associated protein 2 was included in the gel, the sensitivity of the detection of calmodulin-dependent protein kinase II in the gel was more than one order of magnitude higher than that in the gel containing no protein substrate.
...
PMID:A sensitive method for detection of calmodulin-dependent protein kinase II activity in sodium dodecyl sulfate-polyacrylamide gel. 255 25

Data reviewed herein show that the HCl-secreting parietal cell is an exaggerated example of dynamic membrane transformation. Recruitment and recycling of membrane provide the means for the massive redistribution of the gastric proton pump, the H,K-ATPase, from one membrane domain (cytoplasmic tubulovesicles) to another (apical plasma membrane) as a function of parietal cell activation and inactivation. Functional activation of HCl secretion requires not only the redistribution of pump protein, but also the participation of pathways for the rapid flux of K+ and Cl- across the apical membrane. In apical plasma membrane vesicles from stimulated cells these pathways appear to be conductive and can operate independently. Thus, our model for the parietal cell proposes that K+ and Cl- flux from cell to lumen, operating in parallel and in concert with ATP-driven H+/K+ exchange, provides the concentration and osmotic forces required for net HCl secretion. Whether and how the K+ and Cl- pathways are activated by stimulation and/or how they get to the apical membrane domain remain important questions. With respect to mechanisms of parietal cell activation, secretagogue-coupled elevation of cAMP and activation of protein kinase A form the basis of a well-established second messenger pathway. Several laboratories have identified various proteins that are phosphorylated concomitant with parietal cell stimulation, representing numerous candidates for effectors in stimulus-secretion coupling. Here, we emphasized the possible involvement of an 80-kDa protein whose phosphorylation was correlated with the cAMP pathway of HCl secretion. Immunocytolocalization of the 80-kDa phosphoprotein to the apical membrane and associated actin microfilaments prompted our suggestion that this protein might serve as a linkage between plasma membrane and cytoskeleton. Search for a possible role for the 80-kDa phosphoprotein in apical surface organization, stability, and turnover should represent an important thrust of research. Further understanding of the mechanism of cell activation will require a more complete elaboration of the functional role of many activation-related proteins.
...
PMID:Pumps and pathways for gastric HCl secretion. 256 17


1 2 3 4 5 6 7 8 9 10 Next >>

---