Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.17 (CaMKII)
 4,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have studied the effect of protein phosphokinase (EC 2.7.1.37; ATP:protein phosphotransferase) and phosphoprotein phosphatase (EC 3.1.3.16; phosphoprotein phosphohydrolase) on reverse transcriptase (RNA-dependent DNA nucleotidyltransferase) activity of Rous sarcoma virus. Protein kinase from Rous sarcoma virus-transformed chick embryo fibroblasts was purified by DEAE-cellulose chromatography, Sephadex gel filtration, and isoelectric focusing. Purified reverse transcriptase from Rouse sarcoma virus was preincubated with protein kinase and ATP under conditions allowing incorporation of phosphate into substrate protein. After the preincubation, reverse transcriptase activity was assayed in the presence of poly(rA).oligo(dT) as template. A 2- to 5-fold increase of reverse transcriptase activity was found after the preincubation of reverse transcriptase with protein kinase and ATP. Incubation of reverse transcriptase with heat-treated, inactive protein kinase and ATP had no effect on transcriptase activity. When the transcriptase preparation was incubated with protein kinase and [gamma-32P]ATP and subsequently purified by chromatography on phosphocellulose and Sephadex gel filtration, significant amounts of 32P-labeled proteins were found in the fractions exhibiting reverse transcriptase activity, suggesting 32P incorporation into transcriptase or transcriptase-associated proteins. A 20-60% decrease of reverse transcriptase activity was observed after incubation of reverse transcriptase with phosphatase. The results suggest that phosphorylative modification of reverse transcriptase may be critical in the regulation of reverse transcriptase-catalyzed DNA synthesis.
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PMID:Protein kinase and its regulatory effect on reverse transcriptase activity of Rous sarcoma virus. 5 72

An adenosine 3':5'-monophosphate-dependent protein kinase II (ATP:protein phosphotransferase, EC 2.7.1.37) was partially purified from the cytosol fraction of an exponentially growing culture of Tetrahymena pyriformis. Protein kinase II represented approximately 90% of the cytosolic protein kinase activity. The enzyme had a high degree of substrate specificity for calf thymus and Tetrahymena histones as compared to casein, protamine and phosvitin. The enzyme incorporated the terminal phosphate of ATP into serine and threonine residues of all the histone fractions. The apparent Km of the enzyme for adenosine 3':5'-monophosphate (cyclic AMP) was 1-10-minus 8 M. Protein kinase II was also activated by other cyclic nucleotides with apparent Km values in the range 2.k-10-minus 6 M. Ther specific activity of the cyclic AMP-dependent protein kinase of Tetrahymena decreases markedly from initial high values during the transition from the lag to early log phase of growth. This is followed by a shrp increase in the activity of the enzyme as the log phase of growth progresses. The specific activity of the enzyme increases rapidly during the heat-induced synchronization of Tetrahymena cells. The capacity for rapid phosphorylation of multiple classed of organelle-specific phosphoproteins and the level of cyclic AMP were maximal in Tetrahymena during the earliest phase of growth. These results demonstrate that the cell cycle of Tetrahymena may be coordinated by marked variations in the level of cyclic AMP which in turn regulate the cyclic AMP-dependent protein kinase.
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PMID:Changes in cyclic AMP-dependent protein dinase activity in Tetrahymena pyriformis during the growth cycle. 16 17

Chinese hamster ovary cells exhibit several characteristic morphological and physiological responses upon treatment with agents which increase the intracellular level of adenosine 3':5'-phosphate (cyclic AMP). To better understand the mechanism of these cyclic AMP-mediated responses, we separated two cyclic AMP-dependent protein kinases (ATP:protein phosphotransferase, EC 2.7.1.37) (protein kinase I and protein kinase II) from the cytosol of Chinese hamster ovary cells by DEAE-cellulose chromatography and studied their properties. Protein kinase I is eluted at a lower salt concentration than protein kinase II and is stimulable to 10 times its basal catalytic activity, while protein kinase II is stimulable only 2-fold. Both kinases are completely dissociated by cyclic AMP and inhibited by specific cyclic AMP-dependent protein kinase inhibitor. They have similar Km values for magnesium (approximately 1 mM), cyclic AMP (approximately 60 nM), and ATP (approximately 0.1 mM), and the dissociation constant (Kdis) for cyclic AMP (approximately 13 nM) is the same for both enzymes. However, they appear to have different substrate preferences and cyclic AMP-binding properties in that cyclic AMP bound to protein kinase II exchanges readily with free cyclic AMP, while that bound to protein kinase I is not exchangeable. The native enzymes have different sedimentation coefficients (6.4 S for protein kinase I and 4.8 S for protein kinase II), whereas those of the activated enzymes are the same (2.9--3.0 S). It appears that the two cyclic AMP-dependent protein kinases which differ from each other in their regulatory subunits may play different roles in the mediation of cyclic AMP action in Chinese hamster ovary cells.
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PMID:Characterization of two adenosine 3':5'-phosphate-dependent protein kinase species from Chinese hamster ovary cells. 21 11

Protein kinase (ATP:protein phosphotransferase, EC 2.7.1.37) and cyclic adenosine 3',5'-monophosphate binding activities have been identified in zoospore extracts of the water mold Blastocladiella emersonii. More than 75% of these activities is found in the soluble fraction. Soluble protein kinase activity is resolved in three peaks(I, II and III) by DEAE-cellulose chromatography. Peak I is casein dependent and insensitive to cyclic AMP. Peak II is histone dependent and cyclic AMP independent; this enzyme is inhibited by the heat-stable inhibitor from bovine muscle. Peak III utilizes histone as substrate and is activated by cyclic AMP.
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PMID:Cyclic AMP-dependent and -independent protein kinases of the water mold, Blastocladiella emersonii. 22 Oct 23

Protein kinase activity (ATP:protein phosphotransferase, EC 2.7.1.37) has been found associated with the D2 hybrid protein, a highly purified protein of 107,000 daltons specified by the adenovirus-simian virus 40 (SV40) hybrid Ad2(+)D2, which has many properties associated with authentic SV40 T antigen [Tjian, R. & Robbins, A. (1979) Proc. Natl. Acad. Sci. USA 76, 610-614]. We have now examined some of the biochemical characteristics of the reaction products. Acceptors for the terminal phosphoryl group of [gamma-(32)P]ATP are the purified protein itself and at least four proteins extracted from nuclei of uninfected cells. Purified histones do not serve as substrate for the enzyme. Phosphorylation is markedly reduced by heating the D2 hybrid protein to 50 degrees C for 30 min. The products of phosphorylation are stable to treatment with ethanol/ether, DNase, and RNase, but completely degraded by digestion with Pronase, demonstrating their protein nature. The phosphate bonds are liable to hot alkali and sensitive to digestion with alkaline phosphatase but stable to treatment with hot acid or hydroxylamine. These results provide evidence that (32)P is incorporated into O-phosphoserine or O-phosphothreonine residues of acceptor proteins, indicating that the enzymatic activity is characteristic for protein kinase, and that cell-specified nuclear proteins other than histones may serve as substrates for the enzyme.
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PMID:Protein kinase activity associated with the D2 hybrid protein related to simian virus 40 T antigen: some characteristics of the reaction products. 22 74

Two cyclic nucleotide-independent protein kinases (ATP:protein phosphotransferase, EC 2.7.1.37) have been purified to homogeneity from rat liver nuclei. While these enzymes have many similar catalytic properties (preference for acid rather than basic proteins), they differ in molecular weight and subunit composition. Protein kinase NII will utilize ATP and GTP as phosphate donors while protein kinase NI will only effectively use ATP. Both enzymes reveal an unusual activation by Fe2+.
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PMID:Properties of rat liver nuclear protein kinases. 22 67

1. Rat liver microsomal membranes were studied for the presence of protein kinases. Microsomal proteins solubilized with Triton X-100 were analyzed by means of ion exchange chromatography. 2. Protein kinase activity was detected in the column fractions using specific assays for cAMP-dependent protein kinase, cGMP-dependent protein kinase, protein kinase C, Ca2+/calmodulin-dependent protein kinase and casein kinases. 3. Fractions with protein kinase activity were further analyzed by SDS-polyacrylamide gel electrophoresis. 4. The results indicate that cAMP-dependent protein kinase type I and II, casein kinases I and II, protein kinase C proenzymes I and II and Ca2+/calmodulin kinase II are associated with the membranes of endoplasmic reticulum (ER).
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PMID:Rat liver endoplasmic reticulum protein kinases. 818 36

Although the immediate action of organophosphorus esters is the inhibition of acetylcholinesterase, some of these compounds also produce a neurodegenerative disorder known as organophosphorus ester-induced delayed neurotoxicity (OPIDN). Tri-o-cresyl phosphate (TOCP) first produced this condition in humans and later in sensitive animal species. OPIDN is characterized by a delay period prior to onset of ataxia and paralysis. The neuropathologic lesions are Wallerian-type degeneration of the axon and myelin in the distal parts of the large tracts in both the central and peripheral nervous systems. In the past decade we have demonstrated that the pathognomonic features of OPIDN are an aberrant increase in autophosphorylation of calcium/calmodulin kinase II (CaM kinase II) and an increase in phosphorylation of cytoskeletal proteins, i.e., MAPs, tubulin, neurofilament triplet proteins, and myelin basic protein. Protein kinase-mediated phosphorylation of cytoskeletal proteins plays a critical role in regulating the growth and maintenance of the axon. We hypothesize that, in OPIDN, hyperphosphorylation of cytoskeletal proteins and axonal swelling are causally linked. Hyperphosphorylation of cytoskeletal proteins decreases their transport rate down the axon relative to their rate of entry into the axon, thus leading to their accumulation. Consistent with this hypothesis is our finding of the anomalous accumulation of phosphorylated neurofilament aggregates in the central and peripheral axons of hens treated with TOCP.
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PMID:The cytoskeleton as a target for organophosphorus ester-induced delayed neurotoxicity (OPIDN). 834 95

The effect of regucalcin on Ca2+/calmodulin-dependent protein kinase activity in the cytosol of rat renal cortex was investigated. Regucalcin is a calcium-binding protein which exists in rat liver and renal cortex. Protein kinase activity in renal cortex cytosol was markedly increased by the addition of CaCl2 (0.5 mM) plus calmodulin (10 microg/ml) in the enzyme reaction mixture . This increase was completely prevented by the addition of trifluoperazine (25 microM), an antagonist of calmodulin. The cytosolic Ca2+/calmodulin-dependent protein kinase activity was clearly inhibited by the addition of regucalcin; an appreciable effect of regucalcin was seen at 0.01 microM. The cytosolic Ca2+/calmodulin-dependent protein kinase activity was fairly increased by increasing concentrations of added Ca2+ (100-1000 microM). This increase was markedly blocked by the presence of regucalcin (0.1 microM). The inhibitory effect of regucalcin on the protein kinase activity was also seen with varying concentrations of calmodulin (2-20 microg/ml). These results demonstrate that regucalcin can regulate Ca2+/calmodulin-dependent protein kinase activity in renal cortex cells.
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PMID:Inhibitory effect of regucalcin on Ca2+/calmodulin-dependent protein kinase activity in rat renal cortex cytosol. 945 Jun 68

Application of brain-derived neurotrophic factor (BDNF) to hippocampal neurons has profound effects on glutamatergic synaptic transmission. Both pre- and postsynaptic actions have been identified that depend on the age and type of preparation. To understand the nature of this diversity, we have begun to examine the mechanisms of BDNF action in cultured dissociated embryonic hippocampal neurons. Whole-cell patch-clamp recording during iontophoretic application of glutamate revealed that BDNF doubled the amplitude of induced inward current. Coexposure to BDNF and the NMDA receptor antagonist AP-5 markedly reduced, but did not entirely prevent, the increase in current. Coexposure to BDNF and ifenprodil, an NR2B subunit antagonist, reproduced the response observed with AP-5, suggesting BDNF primarily enhanced activity of NR2B-containing NMDA receptors with a lesser effect on non-NMDA receptors. Protein kinase involvement was confirmed with the broad spectrum inhibitor staurosporine, which prevented the response to BDNF. PKCI19-31 and H-89, selective antagonists of PKC and PKA, had no effect on the response to BDNF, whereas autocamtide-2-related inhibitory peptide, an antagonist of CaM kinase II, reduced response magnitude by 60%. These results demonstrate the predominant role of a specific NMDA receptor subtype in BDNF modulation of hippocampal synaptic transmission.
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PMID:Blockade of NR2B-containing NMDA receptors prevents BDNF enhancement of glutamatergic transmission in hippocampal neurons. 1049 7


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