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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)
The present study was conducted to assess the effect of aniracetam and its metabolites, such as 2-pyrrolidinone, p-anisic acid, and anisamide butyrate, on the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, heteromerically formed of GluR1,2 (GluR1 and GluR2), GluR1,3 (GluR1 and GluR3), and GluR1,2,3 (GluR1, GluR2, and GluR3), expressed in Xenopus oocytes. 2-Pyrrolidinone potentiated kainate-evoked currents through GluR1,2,3 channels in a bell-shaped dose-dependent manner at concentrations ranged from 1 nM to 300 microM, with a maximal effect at 100 microM. The potentiation was long-lasting, reaching approximately 180% of basal levels 60 min after 5-min treatment with 2-pyrrolidinone at 100 microM. 2-Pyrrolidinone (100 microM) potentiated GluR1,3 channel currents as observed in GluR1,2,3, but instead it depressed GluR1,2 currents. Aniracetam and p-anisic acid potentiated GluR1,2,3 channel currents, but to a lesser extent, each about 130 and 103% of basal levels 60 min after treatment at 100 microM. In contrast, anisamide butyrate had no potentiating effect on the currents. Potentiation of GluR1,2,3 channel currents obtained with 2-pyrrolidinone was inhibited by KN-93, a selective inhibitor of
calcium/calmodulin-dependent protein kinase
(CaMKII), while it was not affected by GF109203X, a selective inhibitor of protein kinase C or H-89, a selective inhibitor of
cAMP-dependent protein kinase
. The results of the present study suggest that 2-pyrrolidinone persistently enhances activity of the Ca2+-permeable AMPA receptors, GluR1,3 and GluR1,2,3, by interacting with CaMKII.
...
PMID:The aniracetam metabolite 2-pyrrolidinone induces a long-term enhancement in AMPA receptor responses via a CaMKII pathway. 1183 4
Little is known about the mechanisms by which protein-derived nutrients regulate hormone gene expression in the intestine. We have previously reported that protein hydrolysates (i.e. peptones), which are representative of the protein fraction in the lumen, increased cholecystokinin (CCK) gene transcription in the STC-1 enteroendocrine cell line. In the present work, we examined the intracellular events evoked by peptones to stimulate CCK gene transcription. In STC-1 cells, peptones stimulated cyclic AMP production and
protein kinase A
(
PKA
) activity. This was associated with a nuclear translocation of the
PKA
catalytic subunit and with a
PKA
-dependent phosphorylation of the CRE-binding protein (CREB) at Ser(133). Using transient transfection experiments and reporter luciferase assays, we show that peptone-stimulated transcriptional activity of the CCK gene promoter was significantly decreased when the
PKA
pathway was inhibited. Furthermore, the intracellular calcium chelator 1,2-bis-(O-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-tetra(acetoxymethyl)ester completely inhibited peptone-induced stimulation of the CCK gene promoter activity, phosphorylation of CREB, and
PKA
activity. Peptones increased, in a calcium-dependent manner, the phosphorylation of extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) and the MEK inhibitor PD98059 decreased the peptone-induced stimulation of CCK gene promoter activity. This stimulation was also reduced by 30% in the presence of the
calcium/calmodulin-dependent protein kinase
(CaMK) inhibitor KN-93. Total inhibition was obtained when the
PKA
, ERK, and CaMK pathways were simultaneously blocked with appropriate inhibitors to these pathways. These results demonstrate the simultaneous involvement of cAMP- and calcium-dependent protein kinases in the stimulation of intestinal CCK gene transcription by protein-derived nutrients.
...
PMID:Co-requirement of cyclic AMP- and calcium-dependent protein kinases for transcriptional activation of cholecystokinin gene by protein hydrolysates. 1195 Aug 43
Released thyrotropin-releasing hormone (TRH) is inactivated by a narrow specificity ectopeptidase, pyroglutamyl aminopeptidase II (PPII), present in brain and lactotrophs. Various hypothalamic/paracrine factors, including TRH, slowly (in hours) regulate the activity of PPII on the surface of adenohypophyseal cells. TRH-induced down-regulation was mimicked by protein kinase C (PKC) activation but was not affected by inhibition of PKC. Adenylate cyclase activation can also down-regulate PPII. The purpose of this study was to identify elements of the transduction pathway used by TRH to regulate PPII activity. In primary cultures of female adenohypophyseal cells, activation of the stimulatory G protein or adenylate cyclase produced an effect additive to that of TRH; inhibition of
protein kinase A
activity did not interfere with TRH action. However, regulation of PPII activity by TRH was inhibited by a phospholipase C beta inhibitor or chelation of intracellular calcium. L-type calcium channels (LCC) agonists mimicked TRH action and their effect was not additive with that of TRH. Antagonists of LCC channels and inhibitors of calmodulin or
calcium/calmodulin-dependent protein kinase
blocked TRH action. Therefore, TRH-induced calcium entry through L-type calcium channels and the activity of
calcium/calmodulin-dependent protein kinase
are required for TRH effect on PPII activity in primary cultures of adenohypophyseal cells. This pathway may coregulate PPII and prolactin biosynthesis in response to TRH.
...
PMID:Thyrotropin-releasing hormone-induced down-regulation of pyroglutamyl aminopeptidase II activity involves L-type calcium channels and cam kinase activities in cultures of adenohypophyseal cells. 1199 17
Ca(2+)/calmodulin-dependent protein kinase IV (
CaMKIV
) is a multifunctional
protein kinase
expressed abundantly in the central nervous system. Because changes in intracellular Ca(2+) concentrations affect progression through the mitotic cell cycle, enhanced expression of
CaMKIV
has been reported in small cell lung carcinoma and hepatocellular carcinoma. To elucidate the involvement of
CaMKIV
in epithelial ovarian carcinogenesis, we analyzed serial frozen sections for
CaMKIV
protein expression in 26 patients with ovarian epithelial carcinoma and ten patients with benign cystadenoma of the ovary by fluorescent immunohistochemistry. We analyzed the relationship between the percentages of
CaMKIV
-stained cells and the patient's characteristics, including histological classification, clinical stage, histological grade, and clinical outcome. In the benign ovarian cystadenoma,
CaMKIV
was detected in none of the cases examined. Most of the
CaMKIV
proteins were found in the nucleus of epithelial ovarian cancer tissue.
CaMKIV
expression was significantly associated with clinical stage (P<0.01), histological grade (P<0.01), and clinical outcome (P<0.01). Survival data were available for all patients, and univariate Cox regression analysis showed that
CaMKIV
expression was significantly associated with poor prognosis (P<0.05). Our results demonstrate that
CaMKIV
expression in epithelial ovarian cancer correlates with the malignant potential of this tumor.
...
PMID:Ca(2+)/calmodulin-dependent protein kinase IV expression in epithelial ovarian cancer. 1206 94
Calmodulin-dependent
protein kinase
IV (
CaM-kinase IV
) phosphorylated calmodulin (CaM), which is its own activator, in a poly-L-Lys [poly(Lys)]-dependent manner. Although CaM-kinase II weakly phosphorylated CaM under the same conditions, CaM-kinase I, CaM-kinase kinase alpha, and
cAMP-dependent protein kinase
did not phosphorylate CaM. Polycations such as poly(Lys) were required for the phosphorylation. The optimum concentration of poly(Lys) for the phosphorylation of 1 microM CaM was about 10 microg/ml, but poly(Lys) strongly inhibited
CaM-kinase IV
activity toward syntide-2 at this concentration, suggesting that the phosphorylation of CaM is not due to simple activation of the catalytic activity. Poly-L-Arg could partially substitute for poly(Lys), but protamine, spermine, and poly-L-Glu/Lys/Tyr (6/3/1) could not. When phosphorylation was carried out in the presence of poly(Lys) having various molecular weights, poly(Lys) with a higher molecular weight resulted in a higher degree of phosphorylation. Binding experiments using fluorescence polarization suggested that poly(Lys) mediates interaction between the
CaM-kinase IV
/CaM complex and another CaM. The 32P-labeled CaM was digested with BrCN and Achromobacter protease I, and the resulting peptides were purified by reversed-phase HPLC. Automated Edman sequence analysis of the peptides, together with phosphoamino acid analysis, indicated that the major phosphorylation site was Thr44. Activation of CaM-kinase II by the phosphorylated CaM was significantly lower than that by the nonphosphorylated CaM. Thus,
CaM-kinase IV
activated by binding Ca2+/CaM can bind and phosphorylate another CaM with the aid of poly(Lys), leading to a decrease in the activity of CaM.
...
PMID:Phosphorylation of calmodulin by Ca2+/calmodulin-dependent protein kinase IV. 1239 17
Ca2+/calmodulin-dependent protein kinase IV
(
CaMKIV
) is a multifunctional
protein kinase
expressed abundantly in the central nervous system. Because changes in intracellular Ca2+ concentrations affect progression through the mitotic cell cycle, enhanced expression of
CaMKIV
has been reported in small cell lung carcinoma and hepatocellular carcinoma. To elucidate the involvement of
CaMKIV
in endometrial carcinogenesis, we analyzed serial frozen sections from 31 patients with endometrial carcinoma and 20 patients with normal endometria for
CaMKIV
protein expression, using fluorescent immunohistochemistry. We analyzed the relationship between the percentages of
CaMKIV
stained cells and the patient characteristics, including clinical stage, histological grade, myometrial invasion, and clinical outcome. In the normal endometria,
CaMKIV
was detected in none of the cases examined. Most of the
CaMKIV
proteins were found in the nucleus of endometrial carcinoma tissue.
CaMKIV
expression was significantly associated with clinical stage (stage I and II versus stage III and IV; p<0.01), myometrial invasion (no myometrial invasion versus the presence of invasion to greater than one-half the myometrium; p=0.02), and clinical outcome (no evidence of disease versus died of disease; p=0.04). Scoring on the basis of the percentage of positive cells indicated that
CaMKIV
expression was significantly associated with PCNA-labeling index (p=0.02). Our results demonstrate that
CaMKIV
expression in endometrial carcinoma correlates with the malignant potential of this tumor.
...
PMID:CaMKIV expression is associated with clinical stage and PCNA-labeling index in endometrial carcinoma. 1252 74
The application of taurine (2-aminoethanesulfonic acid) induces a long-lasting increase of synaptic efficacy and axon excitability (LLP-TAU) in rat hippocampal CA1 area. After taurine withdrawal, LLP-TAU lasted at least 3 h. This fact prompted us to assess whether the mechanisms involved in the maintenance of this particular potentiation were similar to those implicated in the late phase of long-term potentiation (L-LTP). In the presence of KN-62, an inhibitor of
calcium/calmodulin-dependent protein kinase
, taurine perfusion (10 mM, 30 min) did not affect the induction of LLP-TAU. However, LLP-TAU maintenance was completely suppressed by KT5720, an inhibitor of the
cAMP-dependent protein kinase
(
PKA
). Moreover, the late phase of LLP-TAU was blocked by inhibiting protein synthesis with anisomycin. In addition, taurine perfusion increased the phosphorylation of cAMP response element-binding protein (CREB), although did not affect cAMP levels. These features of LLP-TAU do not appear to be caused by the activation of D1/D5 dopamine receptors, as taurine also induced synaptic potentiation in the presence of SCH23390, an antagonist of this type of receptors. Finally, the late phase of both L-LTP and LLP-TAU occluded mutually. These results suggest that taurine triggers the sequence of some of the molecular events involved in the induction of L-LTP.
...
PMID:Taurine-induced synaptic potentiation and the late phase of long-term potentiation are related mechanistically. 1255 19
Recent studies have demonstrated that transgenic (TG) expression of either
Ca2+/calmodulin-dependent protein kinase IV
(
CaMKIV
) or CaMKIIdeltaB, both of which localize to the nucleus, induces cardiac hypertrophy. However,
CaMKIV
is not present in heart, and cardiomyocytes express not only the nuclear CaMKIIdeltaB but also a cytoplasmic isoform, CaMKIIdeltaC. In the present study, we demonstrate that expression of the deltaC isoform of CaMKII is selectively increased and its phosphorylation elevated as early as 2 days and continuously for up to 7 days after pressure overload. To determine whether enhanced activity of this cytoplasmic deltaC isoform of CaMKII can lead to phosphorylation of Ca2+ regulatory proteins and induce hypertrophy, we generated TG mice that expressed the deltaC isoform of CaMKII. Immunocytochemical staining demonstrated that the expressed transgene is confined to the cytoplasm of cardiomyocytes isolated from these mice. These mice develop a dilated cardiomyopathy with up to a 65% decrease in fractional shortening and die prematurely. Isolated myocytes are enlarged and exhibit reduced contractility and altered Ca2+ handling. Phosphorylation of the ryanodine receptor (RyR) at a CaMKII site is increased even before development of heart failure, and CaMKII is found associated with the RyR in immunoprecipitates from the CaMKII TG mice. Phosphorylation of phospholamban is also increased specifically at the CaMKII but not at the
PKA
phosphorylation site. These findings are the first to demonstrate that CaMKIIdeltaC can mediate phosphorylation of Ca2+ regulatory proteins in vivo and provide evidence for the involvement of CaMKIIdeltaC activation in the pathogenesis of dilated cardiomyopathy and heart failure.
...
PMID:The deltaC isoform of CaMKII is activated in cardiac hypertrophy and induces dilated cardiomyopathy and heart failure. 1267 14
Mammalian circadian rhythms are generated by the hypothalamic suprachiasmatic nuclei and finely tuned to environmental periodicities by neurochemical responses to the light-dark cycle. Light reaches the clock through a direct retinohypothalamic tract, primarily through glutamatergic innervation, and its action is probably regulated by a variety of other neurotransmitters. A key second messenger in circadian photic entrainment is calcium, mobilized through membrane channels or intracellular reservoirs, which triggers the activation of several enzymes, including a
calcium/calmodulin-dependent protein kinase
and nitric oxide synthase. Other enzymes activated by light are mitogen-activated- and
cGMP-dependent protein kinase
; all of the above have been reported to be involved in the circadian responses to nocturnal light pulses. These mechanisms lead to expression of specific clock genes which eventually set the phase of the clock and of clock-controlled circadian rhythms.
...
PMID:From light to genes: moving the hands of the circadian clock. 1270 26
To explore the
protein kinase
family enzymes expressed in cells, we attempted to generate antibodies that could detect a wide variety of protein kinases. For the production of such antibodies, synthetic peptides corresponding to amino acid sequences of a highly conserved subdomain (subdomain VIB) of the
protein kinase
family were used for immunization. Among the various peptide antigens, a peptide with 16 amino acids, CVVHRDLKPENLLLAS, effectively produced polyclonal antibodies with broad cross-reactivities to protein kinases. Two monoclonal antibodies, designated M8C and M1C, detected a variety of protein kinases such as calmodulin-dependent
protein kinase
II,
calmodulin-dependent protein kinase IV
,
cAMP-dependent protein kinase
, and mitogen-activated protein kinases, on Western blotting. The antibodies also immunoprecipitated various protein kinases in cell extracts. Furthermore, these antibodies could be used for detection of positive clones in the expression cloning of various protein kinases. Among 39 positive clones obtained from mouse brain cDNA library, 36 clones were identified as cDNA clones for various known and novel protein serine/threonine kinases, suggesting that the antibodies reacted highly specifically with various protein kinases. These results indicate that the present monoclonal antibodies directed to multiple protein kinases will be a powerful tool for the detection of a variety of known and novel protein kinases in cells.
...
PMID:A new approach for the detection of multiple protein kinases using monoclonal antibodies directed to the highly conserved region of protein kinases. 1459 30
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