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At least 631 records · Page 35Linked to original sources
PubMed2005

Protein interaction of nucleosome assembly protein 1 and casein kinase 2 during desiccation response in the insect-killing nematode Steinernema feltiae IS-6.

The change in gene expression induced by desiccation in the semiarid, entomopathogenic nematode Steinernema feltiae IS-6, includes induction of transcription of a nucleosome assembly protein, NAP1 homolog, and of casein kinase 2 (CK2) genes. Therefore, one of the events during the dehydration response of S. feltiae IS-6 may be transcriptional activation by S. feltiae IS-6 NAP1 homolog (Sf-Nap1), which is regulated by S. feltiae IS-6 CK2 (Sf-CK2). This regulation necessitates physical interaction between the Sf-Nap1 and Sf-CK2 proteins. In the present study we used yeast 2-hybrid analysis to demonstrate physical interaction between the 2 proteins, thus confirming the involvement of a protein interaction-based step in the desiccation response mechanism of S. feltiae IS-6.

Animals↗
PubMed1999

Searching interaction partners of protein kinase CK2beta subunit by two-hybrid screening.

To date, the intracellular regulation of protein kinase CK2 is unknown. However it was observed that the enzyme associates with several intracellular proteins and the formation of such molecular complexes may represent a mechanism for the control of CK2 activity. Using the Interaction Trap system in yeast, with the CK2beta as a bait, we looked for CK2 partners. We present the identification of new potential partners of CK2beta and it is hoped that their classification will help in understanding the physiological roles and the regulation of CK2 in the cell.

Base Sequence↗
PubMed2000

Uncoupling of cell proliferation and differentiation activities of basic fibroblast growth factor.

FGF-2 exerts its pleiotropic effects on cell growth and differentiation by interacting with specific cell surface receptors. In addition, exogenously added FGF-2 is translocated from outside the cell to the nucleus during G1-S transition. In this study, we show that a single point mutation in FGF-2 (substitution of residue serine 117 by alanine) is sufficient to drastically reduce its mitogenic activity without affecting its differentiation properties. The FGF-2(S117A) mutant binds to and activates tyrosine kinase receptors and induces MAPK and p70S6K activation as strongly as the wild-type FGF-2. We demonstrate that this mutant enters NIH3T3 cells, is translocated to the nucleus, and is phosphorylated similar to the wild-type growth factor. This suggests that FGF-2 mitogenic activity may require, in addition to signaling through cell surface receptors and nuclear translocation, activation of nuclear targets. We have previously shown that, in vitro, FGF-2 directly stimulates the activity of the casein kinase 2 (CK2), a ubiquitous serine/threonine kinase involved in the control of cell proliferation. We report that, in vivo, FGF-2(WT) transiently interacts with CK2 and stimulates its activity in the nucleus during G1-S transition in NIH3T3 cells. In contrast, the FGF-2(S117A) mutant fails to interact with CK2. Thus, our results show that FGF-2 mitogenic and differentiation activities can be dissociated by a single point mutation and that CK2 may be a new nuclear effector involved in FGF-2 mitogenic activity.-Bailly, K., Soulet, F., Leroy, D., Amalric, F., Bouche, G. Uncoupling of cell proliferation and differentiation activities of basic fibroblast growth factor (FGF-2).

3T3 Cells↗
PubMed1999

Ischemia induced activation of heat shock protein 27 kinases and casein kinase 2 in the preconditioned rabbit heart.

Protein kinase C (PKC), p38 MAP kinase, and mitogen-activated protein kinase-activated kinases 2 and 3 (MAPKAPK2 and MAPKAPK3) have been implicated in ischemic preconditioning (PC) of the heart to reduce damage following a myocardial infarct. This study examined whether extracellular signal-regulated kinase (Erk) 1, p70 ribosomal S6 kinase (p70 S6K), casein kinase 2 (CK2), and other hsp27 kinases are also activated by PC, and if they are required for protection in rabbit hearts. CK2 and hsp27 kinase activities declined during global ischemia in control hearts, whereas PC with 5 min ischemia and 10 min reperfusion increased their activities during global ischemia. Resource Q chromatography resolved two distinct peaks of hsp27 phosphotransferase activities; the first peak (at 0.36 M NaCl) appeared to correspond to the 55-kDa MAPKAPK2. Erk1 activity was elevated in both control and PC hearts after post-ischemic reperfusion, but no change was observed in p70 S6K activity. Infarct size (measured by triphenyltetrazolium staining) in isolated rabbit hearts subjected to 30 min regional ischemia and 2 h reperfusion was 31.0+/-2.6% of the risk zone in controls and was 10.3+/-2.2% in PC hearts (p<0.001). Neither the CK2 inhibitor 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) nor the Mek1/2 inhibitor PD98059 infused during ischemia blocked protection by PC. The activation of CK2 and Erk1 in ischemic preconditioned hearts appear to be epiphenomena and not required for the reduction of infarction from myocardial ischemia.

Animals↗
PubMed2000

Stanniocalcin 1 and 2 are secreted as phosphoproteins from human fibrosarcoma cells.

Stanniocalcin 1 (STC1) and stanniocalcin 2 (STC2) are two recently identified mammalian peptide hormones. STC1 plays a role in calcium and phosphate homoeostasis, while the role of STC2 is unknown. We examined a human fibrosarcoma cell line, HT1080, that has high steady-state STC1 and STC2 mRNA levels, to determine whether these proteins are secreted. Following incubation of HT1080 cells with (32)P, labelled STC1 and STC2 were found to be secreted into the medium. STC1 was phosphorylated in vitro by protein kinase C (PKC). In vitro and in vivo phosphorylation both occurred exclusively on serine and the phosphopeptide maps were similar, suggesting that PKC might be the in vivo kinase. STC2 was phosphorylated in vitro by casein kinase II (CK2), in vitro and in vivo phosphorylation were exclusively on serine and the phosphopeptide maps were indistinguishable. Phosphorylation of STC2 in intact cells resulted from the action of an ecto-protein kinase, since exogenous STC2 was phosphorylated by HT1080 cells and no phosphorylated STC2 was detectable inside the cells. The ectokinase activity was abolished by heparin and GTP could substitute for ATP as the phosphate donor, indicative of an ecto-CK2-like activity. The in vitro CK2 phosphorylation site was shown by matrix-assisted laser-desorption ionization-time-of-flight MS to be a single serine located between Ser-285 and Ser-298 in the C-terminal region of STC2. This is the first report of the secretion of STC1 or STC2 from mammalian cells. We conclude that these human fibrosarcoma cells express both STC1 and STC2 as secreted phosphoproteins in vivo, with STC2 being phosphorylated by an ecto-CK2-like enzyme.

Blotting, Western↗
PubMed2006

[Inhibitory effects of small interfering RNA specific to protein kinase CK2a on the growth of laryngeal carcinoma cells].

OBJECTIVE: To assess the effect of small interfering RNA (siRNA) specific to protein kinase CK2a on proliferation and apoptosis of Hep-2 cell line. METHODS: siRNA expression plasmid psiRNA-hH1neo-CK2 specific to protein kinase CK2a and non-specific siRNA expression plasmid psiRNA-hH1neo-cont were constructed respectively, and then were transfected into Hep-2 cells by lipofectamine methods. Protein kinase CK2a mRNA and protein of the transfected cells were detected by reverse transcription polymerase chain reaction (RT-PCR) and Western Blot, respectively. Proliferation and apoptosis of the transfected cells were observed by methyl thiazolyl tetrazolium (MTT) method and flow cytometry (FCM), respectively. RESULTS: Protein kinase CK2a mRNA and protein expressions were significantly decreased in the cells transfected with psiRNA-hH1neo-CK2 (P < 0.05). The Hep-2 cells grew slowly after transfected with psiRNA-hH1neo-CK2(P < 0.05). Obvious subdiploid peaks were found in the cells transfected with psiRNA-hH1neo-CK2 (P < 0.05). CONCLUSIONS: siRNA expression plasmid specific to protein kinase CK2a suppressed the protein kinase CK2a expression and the proliferation of Hep-2, and induced apoptosis of Hep-2 cells.

Carcinoma↗
PubMed1982

Electrocardiography, cardioenzymes and myocardial imaging to detect perioperative myocardial infarction.

Serial electrocardiography, technetium-99m pyrophosphate scintigraphy and measurement of myocardial creatine kinase (CK2) and lactic dehydrogenase isoenzyme activity (specifically the LD1 to LD2 ratio) were evaluated prospectively in 26 patients who underwent aortocoronary bypass grafting and 11 patients who underwent valvular or other thoracic surgery, as methods of diagnosing perioperative myocardial infarction. Of the 26 patients who had aorto coronary bypass grafting, 7 (group 1) had myocardial infarction perioperatively; of these, only 2 had positive results from all four diagnostic tests. The other 19 patients (group 2) had no perioperative myocardial infarction and the only diagnostic method yielding positive results was the LD1 to LD2 ratio, in 7 of the 19. In the 11 patients who did not undergo aortocoronary bypass grafting (group 3), only 1 patient had myocardial infarction perioperatively; results from the measurement of CK2 isoenzyme activity and LD1 to LD2 ratio were positive while electrocardiography and 99mTc pyrophosphate scintigraphy yielded negative results. The respective sensitivity (%) and specificity (%) of the four diagnostic methods were as follows: electrocardiography: 38, 100; 99mTc pyrophosphate scintigraphy: 88, 100; LD1 to LD2 ratio: 100, 68; CK2: 38, 100. When the CK2 criterion was redefined, using patients in group 2 as controls, the sensitivity and specificity of this method became 100 and 90 respectively. The authors conclude that 99MTc pyrophosphate scintigraphy and measurement of myocardial creatine kinase isoenzyme are of comparable value and are the most reliable indicators of perioperative myocardial infarction.

Coronary Artery Bypass↗
PubMed1983

Macro--creatine kinase 2: a possible marker of gastrointestinal cancer?

Creatine kinase (CK) is an enzyme found in many body organs. It is used clinically in the diagnosis of myocardial infarction. Recently an atypical isoenzyme, macro-CK2, not found in the sera of healthy individuals, has been reported in patients with gastrointestinal malignancies. This study is a report of our findings in serum samples obtained from 200 patients from November 1981 until December 1982. Twenty-eight patients had gastrointestinal complaints but did not have malignant disease. One hundred seventy-two patients had malignancy. Samples of serum were studied for macro-CK2 with a standard laboratory agarose gel electrophoresis technique. The tests were done without knowledge of the patients' diagnoses. The results show no detectable macro-CK2 in sera from patients without malignancy. It was present before operation in nine of 13 patients with colorectal cancer and 16 of 21 patients with metastases from colorectal cancer or gastric cancer. This preliminary study suggests that the presence of macro-CK2 in serum may be an indicator of malignancy of the gastrointestinal tract and in particular of colorectal cancer.

Adult↗
PubMed1994

Requirement of casein kinase 2 for entry into and progression through early phases of the cell cycle.

Requirement of protein kinase CK2 during cell cycle was examined by specific perturbation of CK2 in the intact cell by antisense-oligodeoxynucleotides and microinjection of antibodies. When quiescent human primary lung fibroblasts (IMR-90) were exposed before growth stimulation to oligodeoxynucleotides complementary to the translation start region of mRNAs encoding subunit alpha or beta, a significant inhibition of growth stimulation by epidermal growth factor or serum was observed. The inhibition was reversible and decreased or abolished with mutated antisense-oligodeoxynucleotides. The inhibitory effect coincided with a decrease of CK2 protein (immunostaining with beta subunit antibody) at entry into and during the first several hours of the cell cycle. Injection of beta-specific monoclonal and polyclonal antibodies into IMR-90 cells caused significant inhibition of growth stimulation. The inhibition was reversible, not observed with control antibodies, and strongly reduced by coinjection of CK2 holoenzyme. Cytoplasmic injection inhibited up to 50-60% and was effective at two intervals within the first 2 h and at 12-16 h poststimulation, i.e., at G0/G1 phase transition and at G1/S boundary, respectively. The inhibition at G0/G1 transition is paralleled by an inhibition of cytoplasmic-nuclear translocation of beta subunit protein. Injection of beta antibodies into the nucleus inhibited growth stimulation by as much as 80-85% and was effective for the first 6 h poststimulation, i.e., at G0/G1 phase transition and progression through the adjoining early G1 phase. Nuclear as well as cytoplasmic injections performed during S phase affected neither DNA synthesis nor cell division.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1994

Human larynx carcinoma cells resistant to cis-diamminedichloroplatinum(II): mechanisms involved in the resistance.

The aim of this study was to characterize two cis-diamminedichloroplatinum(II) (CDDP) resistant cell lines established from human larynx carcinoma HEp2 cells through repeated treatments with increased CDDP concentrations. CK2 cells obtained by continuous treatments were more resistant to CDDP than CA3 cells obtained by acute treatments. The examination of growth characteristics showed that both CDDP resistant cells had doubling times identical to that of the parental cells, but had lower plating efficiency. The possible involvement of glutathione (GSH), glutathione transferases (GST), metallothioneins, P-glycoprotein and drug accumulation in CDDP resistance was examined. Glutathione contents were elevated in both CDDP resistant lines. However, neither GSH nor GST were involved in CDDP resistance. This was demonstrated by simultaneous incubation of parental and CDDP resistant cells with CDDP and specific inhibitors of GSH and GST alpha and pi (buthionine sulfoximine and ethacrinic acid). Similarly, verapamil, an inhibitor of P-glycoprotein, did not influence the sensitivity of parental and resistant cells to CDDP. As compared to the parental cells, CK2 cells became resistant and CA3 cells became sensitive to cadmium, indicating increased level of metallothioneins in CK2 cells, and reduced level in CA3 cells. Measurements of platinum contents in parental and CDDP resistant cells after 1, 3 and 6 hours exposure to 70 mumol CDDP showed reduction in platinum accumulation after each exposure time in CK2 cells, and after 6 hours exposure in CA3 cells. This study identified decreased platinum accumulation as an important mechanism of CDDP resistance in human larynx carcinoma cells.

Buthionine Sulfoximine↗
PubMed2006

Neuron-specific enolase-cre mouse line with cre activity in specific neuronal populations.

To establish genetic tools for conditional gene deletion in mouse neurons, we generated two independent neuron-specific enolase (Nse)-cre transgenic lines. The transgenic line termed Nse-cre(CK1) showed cre activity in most neuronal regions in the nervous system, while the Nse-cre(CK2) line exhibited a unique cre activity that has not been reported in other cre transgenic lines. Nse-cre(CK2) cre activity was detectable from embryogenesis and mostly restricted to neuronal regions. In postnatal brain, the Nse-cre(CK2) line exhibited cre activity limited to differentiated neurons in the cerebral cortex and hippocampus. Cre activity was assayed in several internal organs and sporadic activity was limited to the kidney and testis. We conclude that these cre lines will be useful for studying loss of gene function in specific neuronal populations.

Animals↗
PubMed2002

Human papillomavirus-16 E7 protein inhibits the DNA interaction of the TATA binding transcription factor.

Previous studies have shown that the HPV-16 E7 protein interacts with TBP. This interaction was found to take place through residues in the carboxy terminal half of E7, mutation of which resulted in weaker transforming activity. In addition, binding of E7 to TBP was found to be increased following protein kinase CK2 (casein kinase II) phosphorylation of E7, and mutation of this CK2 site also reduces E7's transforming activity. To date, however, there is no information on the effects of E7 upon TBP function. In order to address this we have performed a series of assays to investigate the effects of E7 upon the ability of human and S. pombe TBP to bind DNA. We show that HPV-16 E7 is indeed a potent inhibitor of TBP DNA binding activity. Further, this activity of E7 is increased following CK2 phosphorylation of E7, consistent with it having an increased affinity for TBP. Finally, a mutant E7 protein defective in its ability to bind TBP, has no effect upon TBP binding to DNA. These results demonstrate that one consequence of the E7-TBP interaction is abolition of TBP DNA binding activity, and may provide an explanation for the transcriptional inhibitory effects of E7.

Animals↗
PubMed1997

Phosphorylation of osteopontin by Golgi apparatus casein kinase.

Osteopontin (OPN) is a ubiquitous multiphosphorylated secretory glycoprotein. Twenty-seven phosphorylated serines have been identified in bovine milk OPN (E. S. Sorensen et al. (1995) Protein Sci. 4, 2040-2049). Nineteen of these phosphoacceptor sites are fully conserved in rat OPN, all displaying the consensus for the Golgi apparatus casein kinase, G-CK (S-x-E/Sp). Here we show that rat OPN is indeed phosphorylated more readily than casein itself by G-CK from either rat mammary gland or liver. OPN is also phosphorylated by casein kinases-1 and -2 (CK1, CK2), though less readily than casein. If OPN kinase activities are normalized in terms of casein phosphorylation, OPN phosphorylation rate by G-CK is 78-fold and 19-fold higher than those measured with CK2 and CK1, respectively. These data, in conjunction with the specific location of G-CK to the Golgi apparatus, where CK2 and CK1 are hardly detectable, support the view that G-CK is the main if not the only physiological agent committed to the phosphorylation of OPN.

Amino Acid Sequence↗
PubMed1999

Protein kinases phosphorylating acidic ribosomal proteins from yeast cells.

Phosphorylation of ribosomal acidic proteins of Saccharomyces cerevisiae is an important mechanism regulating a number of active ribosomes. The key role in the regulatory mechanism is played by specific phosphoprotein kinases and phosphoprotein phosphatases. Three different cAMP-independent protein kinases phosphorylating acidic ribosomal proteins have been identified and characterized. The protein kinase 60S (PK60S), RAP kinase, and casein kinase type 2 (CK2). All three protein kinases phosphorylate serine residues which are localized in the C-terminal end of phosphoproteins. Synthetic peptides were used to determinate the amino acid sequence of phosphoacceptor site for PK60S. Peptide AAEESDDD derived from phosphoproteins YP1 beta/beta' and YP2 alpha turned out to be the best substrate for PK60S. A number of halogenated benzimidazoles and 2-azabenzimidazoles were tested as inhibitors of the three protein kinases. 4,5,6,7-Tetrabromo-2-azabenzimidazole inhibits phosphorylation only of these polypeptides phosphorylated by protein kinase 60S, namely YP1 beta/beta' and YP2 alpha, but not the other, YP1 alpha and YP2 beta phosphorylated by protein kinases RAP and CK2. RAP kinase has been found in an active form in the soluble fraction of S. cerevisiae. The enzyme uses ATP as a phosphate donor and is less sensitive to heparin than casein kinase 2. RAP kinase monophosphorylates the four acidic proteins. The ribosome-bound proteins are a better substrate for the enzyme. Multifunctional CK2 kinase phosphorylate all four acidic proteins. The kinase phosphorylates preferentially serine or threonine residues surrounded by cluster of acidic residues. The enzyme activity is stimulated in vitro by the presence of polylysine and inhibited by heparin.

Casein Kinase II↗
PubMed1986

Keratin polypeptide distribution in benign and malignant breast tumors: subdivision of ductal carcinomas using monoclonal antibodies.

Monoclonal antibodies which recognize one or only a few keratin polypeptides have been used to study the distribution of different keratins in benign and malignant breast lesions by immunocytochemical methods. Seven monoclonal antibodies which recognized either different keratin polypeptides by immunoblotting techniques, or identified different epithelial cell types in complex tissues were used. In two mastopathies and three fibroadenomas the antibody lu5 stained luminal cells as well as myoepithelial cells. In contrast the antibodies CK7, Troma 1, CK2 and KA4 labeled only luminal cells, whereas antibody CKB1 decorated only myoepithelial cells. All 15 ductal carcinomas showed a uniform staining of tumor cells with the antibodies Troma 1, CK2, KA4 and lu5. The antibody CK7 also stained all ductal carcinomas, but in two specimens the staining was heterogeneous. The antibody CKB1 decorated only the pre-existing myoepithelial cells in 11 of 12 ductal carcinomas but in the remaining specimen the tumor cells were also strongly positive. Tumor cells in lobular carcinomas were labeled by antibodies CK7, Troma 1, CK2, KA4, bu not by CKB1. The antibody CKS1 showed no staining of any of the benign and malignant breast lesions.

Antibodies, Monoclonal↗
PubMed2005

Biochemical characterization of the recombinant human Drosophila homologues Timekeeper and Andante involved in the Drosophila circadian oscillator.

The Drosophila clock proteins timekeeper (CK2a(Tik)) and andante (CK2beta(And)) are mutated CK2alpha and CK2beta subunits, respectively. In order to revisit the hypothesis concerning a perturbation of the beta/beta and/or alpha/beta subunit association, involving the andante mutant we have cloned, expressed and purified the recombinant andante mutant CK2beta(And) and a CK2 holoenzyme composed of CK2beta(And) and the wildtype CK2alpha subunit. Biochemical analyses using gel filtration analysis, inhibitor and heat treatment, as well as urea denaturation studies did not yield significant differences between the wildtype holoenzyme (alpha2beta2) and a holoenzyme containing wildtype CK2alpha and andante CK2beta(And). The timekeeper mutant, CK2alpha(Tik) has been reported to show a significant reduction in enzyme activity. In order to closely investigate the reason for this reduction in activity, we have also cloned and expressed the human homologue of Drosophila timekeeper. Using a CK2 holoenzyme containing the human timekeeper mutant and the wildtype CK2beta subunit we could confirm a strongly reduced activity towards CK2 substrates, but also a significant reduction in the autophosphorylation of the CK2beta in the absence of any substrate. Based on a structure-based model we postulate that the mutation M161K in Drosophila (i.e. M163K in human) is responsible for the drastic loss of activity, where the lysine residue may cause improper binding of the tri-nucleotide.

Amino Acid Sequence↗
PubMed1993

Resistance of human larynx carcinoma cells to cisplatin, gamma-irradiation and methotrexate does not involve overexpression of c-myc or c-Ki-ras oncogenes.

In our previous study, we achieved resistance to cisplatin or vincristine (VCR) by repeated treatments of human larynx carcinoma HEp2 cells with these drugs. Resistant cells were cloned and four clones were selected: CA3 and VA3 clones were selected from cells acutely treated with cisplatin or VCR, while CK2 and VK2 cells were selected from cells chronically treated with cisplatin and VCR, respectively. The aim of this study was to examine whether the development of resistance to cisplatin and vincristine changes the expression of c-myc and c-Ki-ras oncogenes and to determine whether there is a correlation between the expression of these oncogenes and the sensitivity of selected clones to cisplatin, methotrexate and gamma-rays. The cell sensitivity to cisplatin, methotrexate and gamma-rays was determined on the basis of the clonogenic survival assay. The expression of c-myc and c-Ki-ras oncogenes was examined by the use of RNA dot blot and Northern blot analyses. The results show that the development of resistance to selected drugs does not alter the expression of either c-myc or c-Ki-ras oncogene. CA3 and CK2 clones were resistant to cisplatin, while the vincristine resistant clones VA3 and VK2 became sensitive to this drug. The sensitivity of resistant clones to gamma-rays varied. CA3 cells were resistant, VA3 and VK2 cells sensitive, while CK2 cells exhibited the same sensitivity to gamma-rays as did the parental cells. All four clones tested became cross-resistant to methotrexate. We can conclude that development of resistance to cisplatin and vincristine does not alter the expression of c-myc or c-Ki-ras oncogene. We did not find any correlation between expression of these oncogenes and the sensitivity to cisplatin, methotrexate or gamma-rays.

Blotting, Northern↗
PubMed1993

The autophosphorylation and p34cdc2 phosphorylation sites of casein kinase-2 beta-subunit are not essential for reconstituting the fully-active heterotetrameric holoenzyme.

Two mutants of human casein kinase-2 beta-subunit with short deletions at either their amino (delta 1-4) or carboxy (delta 209-215) terminal side have been created that have lost the capability to undergo autophosphorylation and p34cdc2 mediated phosphorylation, respectively. Both mutants give rise to reconstituted CK2 holoenzymes displaying basal catalytic activity, thermostability and responsiveness to polylysine, identical to those of wild-type holoenzyme, whose reconstitution, moreover, is not affected by previous phosphorylation of the beta-subunit at either its N-terminal or C-terminal sites. Unlike the wild-type beta and beta(delta 209-215), however, beta(delta 1-4) fails to confer to the reconstituted holoenzyme the typical responsiveness to NaCl stimulation. These results suggest that while neither the autophosphorylation nor the p34cdc2 phosphorylation sites are required for conferring a stable structure and full catalytic activity to CK2, the autophosphorylation site is implicated in the NaCl-dependent fine tuning of CK2 activity.

Amino Acid Sequence↗