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)

Activities of glycogen synthase (total) and branching enzyme in slow (soleus) muscle are higher than those in fast (vastus lateralis) muscle, while those of phosphorylase kinase (total), phosphorylase (total) and debranching enzyme are reversed. The active form ratio of glycogen synthase is higher in fast muscle, while those of phosphorylase kinase and phosphorylase are higher in slow muscle. Activities of cAMP-dependent protein kinase and protein phosphatase in slow muscle are higher than those in fast muscle. These results suggest that glycogen metabolizing enzymes in slow muscle, distinct from those in fast muscle, are regulated more strongly by cAMP-dependent protein kinase rather than by protein phosphatase.
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PMID:Comparison of enzyme activities on glycogen metabolism in rabbit slow and fast muscles. 299 76

Insulin causes rapid phosphorylation of the beta subunit (Mr = 95,000) of its receptor in broken cell preparations. This occurs on tyrosine residues and is due to activation of a protein kinase which is contained in the receptor itself. In the intact cell, insulin also stimulates the phosphorylation of the receptor and other cellular proteins on serine and threonine residues. In an attempt to find a protein that might link the receptor tyrosine kinase to these serine/threonine phosphorylation reactions, we have studied the interaction of a partially purified preparation of insulin receptor with purified preparations of serine/threonine kinases known to phosphorylate glycogen synthase. No insulin-dependent phosphorylation was observed when casein kinases I and II, phosphorylase kinase, or glycogen synthase kinase 3 was incubated in vitro with the insulin receptor. These kinases also failed to phosphorylate the receptor. By contrast, the insulin receptor kinase catalyzed the phosphorylation of the calmodulin-dependent kinase and addition of insulin in vitro resulted in a 40% increase in this phosphorylation. In the presence of calmodulin-dependent kinase and the insulin receptor kinase, insulin also stimulated the phosphorylation of calmodulin. Phosphoamino acid analysis showed an increase of phosphotyrosine content in both calmodulin and calmodulin-dependent protein kinase. These data suggest that the insulin receptor kinase may interact directly and specifically with the calmodulin-dependent kinase and calmodulin. Further studies will be required to determine if these phosphorylations modify the action of these regulatory proteins.
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PMID:Interaction of the insulin receptor kinase with serine/threonine kinases in vitro. 300 Nov 7

In order to achieve further clarification of the regulation of glycogenolysis in adipose tissue, we studied the effect of glucose-6-phosphate on phosphorylase activation in Sephadex G-25 filtrate of adipose tissue. The activity of phosphorylase kinase was decreased by 50% and by 75% in the presence of 0.5 mM and 2 mM of glucose-6-phosphate, respectively. This inhibition could be partially prevented by 0.5 mM AMP. Furthermore, we investigated the influence of glucose-6-phosphate on the effect of cyclic-AMP-dependent protein kinase on the activation of phosphorylase. The addition of cyclic-AMP and cyclic-AMP-dependent protein kinase caused a decrease in the inhibition of the phosphorylase activation by glucose-6-phosphate. Also, the glucose-6-phosphate at physiological concentration, decreased adipose tissue cyclic-AMP-dependent protein kinase activity.
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PMID:Involvement of cyclic AMP-dependent protein kinase on the phosphorylase kinase inhibition by glucose-6-phosphate in adipose tissue extracts. 300 47

The isolated glycogen particle provides a means to examine the regulation of glycogen metabolism with the components organized in a functional cellular complex. With this system, we have studied the control of phosphorylase kinase activation by Ca2+ and cAMP. Contrary to a previous report (Heilmeyer, L. M. G., Jr., Meyer, F., Haschke, R. H., and Fisher, E. H. (1980) J. Biol. Chem. 245, 6649-6656), phosphorylase kinase became activated during incubation of the glycogen particle with MgATP2- and Ca2+. Part of this activation could be attributed to the action of the cAMP-dependent protein kinase; however, it was not possible to quantitatively correlate activation with phosphorylation in the presence of Ca2+ and Mg2+ due to a large, but uncertain, contribution of synergistic activation caused by these ions. This latter activation had properties similar to those described by King and Carlson (King, M. M., and Carlson, G. M. (1980) Arch. Biochem. Biophys. 209, 517-523) with the purified enzyme, and its occurrence also explains why phosphorylase kinase activation in the glycogen particle was not observed previously. The cAMP-dependent activation of phosphorylase kinase in the glycogen particle has been characterized. It occurred in a similar manner when either the cAMP-dependent protein kinase or cAMP was added, thus indicating that the phosphorylation sites of phosphorylase kinase complexed in the glycogen particle were accessible to endogenous or exogenous enzyme. In the glycogen particle, both the alpha and beta subunits were phosphorylated by the cAMP-dependent protein kinase, but the alpha subunit dephosphorylation appeared to be preferentially regulated by Ca2+. The activity of phosphorylase kinase in the glycogen particle is regulated by the phosphorylation of both the alpha and beta subunits.
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PMID:Control of phosphorylase kinase in the isolated glycogen particle by Ca2+-Mg2+ synergistic activation and cAMP-dependent phosphorylation. 300 4

A comparative study on the structure of nonactivated and activated forms of phosphorylase kinase was carried out. The enzyme was activated by incubation in alkaline medium (pH 8.5), by phosphorylation with cAMP-dependent protein kinase and by limited proteolysis. The comparative analysis was based on the use of hydrophobic chromatography on phenyl-sepharose and electrophoresis in polyacrylamide gel density gradient. Activation of the enzyme was accompanied by separation of a low molecular weight component (Mr about 17 000). Using chromatography on phenyl-sepharose, this low molecular weight protein was obtained in a homogeneous state. It was found that the properties of the protein are close to those of calmodulin. The presence of calmodulin in phosphorylase kinase preparations was judged upon by the activation of the calmodulin-dependent form of phosphodiesterase. The boiled and subtilisin-treated kinase activates phosphodiesterase in the same way as does bovine brain calmodulin. The experimental results suggest that the delta-subunit is a protein inhibitor of the enzyme.
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PMID:[The role of calmodulin (delta-subunit) in the activation of phosphorylase kinase from rabbit skeletal muscles]. 301 Nov 26

Immunoaffinity purified pp60v-src was found to activate the MgATP-dependent protein phosphatase in the presence of MgATP. Although preliminary evidence suggested that phosphorylation of the inhibitor-2 subunit on tyrosine residues was responsible for the activation, preincubation of the pp60v-src preparation at 41 degrees C resulted in a rapid loss of its protein kinase activities towards both casein and inhibitor-2 while its ability to activate the protein phosphatase complex was relatively insensitive to this treatment. This result demonstrated that pp60v-src was not responsible for activation of the MgATP-dependent protein phosphatase. A protein kinase activity which phosphorylated glycogen synthase on serine residues was detected in the pp60v-src preparation. The protein kinase was active in the presence of inhibitors of phosphorylase kinase, glycogen synthase kinase 5/casein kinase II, and cAMP-dependent protein kinase. It is, therefore, likely that activation of the MgATP-dependent protein phosphatase resulted from the presence of a glycogen synthase kinase 3 like activity in the pp60v-src preparation. Our results illustrate the importance of applying multiple criteria to link the phosphorylation of a protein with an observed change in its activity.
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PMID:Apparent activation of the MgATP-dependent protein phosphatase by pp60v-src. Identification of an activity like that of glycogen synthase kinase 3 in immunoaffinity purified pp60v-src preparations. 301 36

The effect of glucagon and insulin on rat liver phosphorylase phosphatase activity in vivo was investigated. The activity of phosphatase was found to decrease following the administration of glucagon and increase with insulin in a reversible manner. No change was detected in the activity of heat-stable phosphatase inhibitors in the hormone-treated samples. Liver protein kinases (regulatory subunit of cAMP-dependent protein kinase and/or Ca2+-dependent phosphorylase kinase) are suggested to regulate the activity of hepatic phosphorylase phosphatase (type 1 and 2A).
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PMID:Hormonal regulation of phosphorylase phosphatase activity in rat liver. 301 75

Many hormones and neurotransmitters exert their biological effects by increasing the levels of Ca2+ and 1,2-diacylglycerol in their target cells. Major agonists that act in this way are epinephrine and norepinephrine, acetylcholine, vasopressin, cholecystokinin, and angiotensin II. These and other Ca2+-mobilizing agonists may also produce effects that are not mediated by Ca2+ or diacylglycerol, but involve separate receptors and an increase or decrease in cyclic AMP. The general mechanisms by which Ca2+-mobilizing agonists induce their physiological responses are depicted in Fig. 12. These responses appear to involve an initial mobilization of Ca2+ from endoplasmic reticulum and perhaps other intracellular Ca2+ stores, followed by alterations in the flux of Ca2+ across the plasma membrane. The Ca2+ changes are consistently associated with increased turnover of cellular phosphoinositides. The most rapid response is breakdown of phosphatidylinositol 4,5-P2 in the plasma membrane, and there is much evidence that this involves a guanine-nucleotide-binding regulatory protein similar to those involved in the regulation of adenylate cyclase. Myo-inositol 1,4,5-P3 produced by phosphatidylinositol 4,5-P2 breakdown rapidly releases Ca2+ from endoplasmic reticulum, and it is likely that it is the long-sought second message for the Ca2+-dependent hormones. 1,2-Diacylglycerol, the other product of phosphatidylinositol 4,5-P2 breakdown, also acts as a second message in that it activates protein kinase C, a Ca2+-phospholipid-dependent protein kinase, by lowering its requirement for Ca2+. The cellular substrates for protein kinase C and its role in the different physiological responses to the Ca2+-mediated agonists are currently being defined. The major intracellular target for Ca2+ is the Ca2+-dependent regulatory protein calmodulin. This binds Ca2+ with high affinity, and the resulting complex interacts with a variety of enzymes and other cellular proteins, modifying their activities. A major target is the multifunctional calmodulin-dependent protein kinase that phosphorylates and alters the activities of many proteins, for example, glycogen synthase and tyrosine hydroxylase. Calcium ions may also stimulate calmodulin-dependent protein kinases that are more specific, such as phosphorylase kinase and myosin light-chain kinase. Other important Ca2+-calmodulin targets are the microtubule-associated proteins, but it is likely that many more will be found.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Mechanisms involved in calcium-mobilizing agonist responses. 302 85

Rat liver glycogen synthase was phosphorylated by purified protein kinase C in a Ca2+- and phospholipid-dependent fashion to 1-1.4 mol PO4/subunit. Analysis of the 32P-labeled tryptic peptides derived from the phosphorylated synthase by isoelectric focusing and two-dimensional peptide mapping revealed the presence of a major radioactive peptide. The sites in liver synthase phosphorylated by protein kinase C appears to be different from those phosphorylated by other kinases. Prior phosphorylation of the synthase by protein kinase C has no significant effect on the subsequent phosphorylation by glycogen synthase (casein) kinase-1 or kinase Fa, but prevents the synthase from further phosphorylation by cAMP-dependent protein kinase, Ca2+/calmodulin-dependent protein kinase, phosphorylase kinase, or casein kinase-2. Additive phosphorylation of liver glycogen synthase can be observed by the combination of protein kinase C with the former set of kinases but not with the latter. Phosphorylation of liver synthase by protein kinase C alone did not cause an inactivation nor did the combination of this kinase with glycogen synthase (casein) kinase-1 or kinase Fa produce a synergistic effect on the inactivation of the synthase. Based on these findings we conclude that the phorbol ester-induced inactivation of glycogen synthase previously observed in hepatocytes cannot be accounted for entirely by the activation of protein kinase C.
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PMID:Role of protein kinase C in the regulation of rat liver glycogen synthase. 302 62

Rat tissue levels of Ca2+ . calmodulin-dependent protein kinase II (protein kinase II) and Ca2+ . phospholipid-dependent protein kinase (protein kinase C) were selectively assayed using the synthetic peptide syntide-2 as substrate. The sequence of syntide-2 (pro-leu-ala-arg-thr-leu-ser-val-ala-gly-leu-pro-gly-lys-lys) is homologous to phosphorylation site 2 in glycogen synthase. The relative Vmax/Km ratios of the known Ca2+-dependent protein kinases for syntide-2 were determined to be as follows: protein kinase II, 100; protein kinase C, 22; phosphorylase kinase, 2; myosin light chain kinase, 0.005. Levels of protein kinase II were highest in cerebrum (3.36 units/g tissue) and spleen (0.85 units/g) and lowest in testis (0.05 units/g) and kidney (0.04 units/g). Protein kinase II activity was localized predominantly in the 100,000g particulate fraction of cerebrum and testis, in the supernatant fraction of heart, liver, adrenal, and kidney, and about equally distributed between particulate and supernatant in spleen and lung. Likewise, protein kinase C activity was highest in cerebrum (0.56 units/g) and spleen (0.47 units/g), and the majority of activity was present in the cytosolic fraction for all tissues measured except for cerebrum and testis in which the kinase activity was equal in both fractions. Finally, the ratios of protein kinase II to protein kinase C were different in various rat tissues and between particulate and supernatant fractions. These results suggest somewhat different functions for these two Ca2+-regulated, multifunctional protein kinases.
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PMID:Calcium . calmodulin-dependent protein kinase II and calcium . phospholipid-dependent protein kinase activities in rat tissues assayed with a synthetic peptide. 302 65


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