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)

A lymphocyte-specific protein, p50, is phosphorylated on Ser and Thr residues in mitogen-activated T cells, suggesting that this molecule plays some role in the T cell activation cascade. p50 was identified as lymphocyte specific protein 1 (LSP1), which is a putative calcium-binding protein. In the present study, to clarify the role of p50 protein in the cascade, in vivo and in vitro phosphorylation of this molecule, and the effect of the phosphorylation on its distribution in activated T cells were examined. First, to obtain a sufficient amount of p50 as a phosphorylation substrate, p50 cDNA, which encodes a protein of 330 amino acid residues with a molecular mass of 36,728 Da, was cloned from an ICR mouse thymocyte cDNA library and expressed in Escherichia coli. When the putative coding region of p50 cDNA was expressed in E. coli, the product showed an apparent molecular mass of 50 kDa on SDS-PAGE. The recombinant p50 was phosphorylated in vitro by rabbit protein kinase C (PKC) and by murine cytosolic protein kinase, that was activated by a combination of phosphatidylserine and diacylglycerol. Furthermore, p50 was shown to be phosphorylated on the same sites in T cells upon stimulation with Con A as when phosphorylated in vitro by rabbit PKC, indicating that p50 is phosphorylated by PKC in Con A-stimulated T cells. On subcellular fractionation followed by immunoblotting analysis, membrane-bound p50 was shown to be released from the membrane following activation of PKC in T cells. These results and the recent finding that p50 binds to actin fibers raise the possibility that p50 controls the binding of actin fibers to the plasma membrane under regulation by PKC in T cells.
...
PMID:Protein kinase C phosphorylates p50 LSP1 and induces translocation of p50 LSP1 in T lymphocytes. 777 93

A vincristine-resistant lymphoma cell line (HOB1/VCR1.0) that is resistant to 1.0 microM of vincristine has been established from a human immunoblastic B lymphoma cell line, HOB1. HOB1/VCR1.0 cells demonstrated the typical multidrug resistant phenotypes. Using two-dimensional gel electrophoresis, we discovered one protein with a molecular mass of 22 kDa and pI 5.7 that was overexpressed in HOB1/VCR1.0 cells. This protein was purified to the degree of apparent homogeneity by preparative isoelectric focusing and sodium dodecylsulfate-polyacrylamide gel electrophoresis. The identification of this protein with sorcin was revealed by comparing the internal amino acid sequence of three Lys-C digested peptides from the purified protein with the sequence previously determined for hamster sorcin. The complete primary structure of the human sorcin was deduced from nucleotide sequence analysis of its cDNA clones. It is composed of 198 amino acid residues with a calculated molecular weight of 21,676, and its sequence is highly similar to that of hamster sorcin (95%). Direct-binding assay with calcium showed that human sorcin is a calcium-binding protein with four 'E-F hand' structures typical of calcium-binding sites. Like the sorcin of hamster, two of the calcium-binding sites of human sorcin contain putative recognition sites for cAMP-dependent protein kinase. Southern and Northern blot analyses showed that the human sorcin gene was greatly amplified and overexpressed in resistant HOB1/VCR1.0 cells but not detected in the parental HOB1 cells. The overproduction of this protein in resistant cells implies that sorcin plays a role in expression of the resistant phenotype.
...
PMID:Isolation and molecular cloning of human sorcin a calcium-binding protein in vincristine-resistant HOB1 lymphoma cells. 787 2

The second messenger molecules cAMP and Ca2+ regulate a large number of eukaryotic cellular events. cAMP acts on protein kinases, and Ca2+ works through a ubiquitous calcium-binding protein, calmodulin. The 2 systems are not independent, however, but interact in several important fashions. These interactions can be demonstrated by calmodulin-dependent phosphodiesterase. The bovine heart calmodulin-dependent phosphodiesterase can be phosphorylated by cAMP-dependent protein kinase, resulting in a decrease in the enzyme's affinity for calmodulin. The phosphorylation of calmodulin-dependent phosphodiesterase is blocked by Ca2+ and calmodulin, and reversed by the calmodulin-dependent phosphatase (calcineurin). The dephosphorylation is accompanied by an increase in the affinity of the phosphodiesterase for calmodulin. Results from this study suggest that the activity of this phosphodiesterase is precisely regulated by cross-talk between Ca2+ and cAMP signalling pathways.
...
PMID:Molecular interaction between cAMP and calcium in calmodulin-dependent cyclic nucleotide phosphodiesterase system. 798

R2D5 is a mouse monoclonal antibody that labels rabbit olfactory receptor neurons. Immunoblot analysis showed that mAb R2D5 recognizes a 22-kD protein with apparent pI of 4.8, which is abundantly contained in the olfactory epithelium and the olfactory bulb. We isolated cDNA for R2D5 antigen and confirmed by Northern analysis and neuronal depletion technique that R2D5 antigen is expressed predominantly, but not exclusively, in olfactory receptor neurons. Analysis of the deduced primary structure revealed that R2D5 antigen consists of 189 amino acids with calculated M(r) of 20,864 and pI of 4.74, has three calcium-binding EF hands, and has possible phosphorylation sites for Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) and cAMP-dependent protein kinase (A kinase). Using the bacterially expressed protein, we directly examined the biochemical properties of R2D5 antigen. R2D5 antigen binds Ca2+ and undergoes a conformational change in a manner similar to calmodulin. R2D5 antigen is phosphorylated in vitro by CaM kinase II and A kinase at different sites, and 1.81 and 0.80 mol of Pi were maximally incorporated per mol of R2D5 antigen by CaM kinase II and A kinase, respectively. Detailed immunohistochemical study showed that R2D5 antigen is also expressed in a variety of ependymal cells in the rabbit central nervous system. Aside from ubiquitous calmodulin, R2D5 antigen is the first identified calcium-binding protein in olfactory receptor neurons that may modulate olfactory signal transduction. Furthermore our results indicate that olfactory receptor neurons and ependymal cells have certain signal transduction components in common, suggesting a novel physiological process in ependymal cells.
...
PMID:R2D5 antigen: a calcium-binding phosphoprotein predominantly expressed in olfactory receptor neurons. 822 52

An unusual protein kinase gene, termed PfCPK, was isolated from Plasmodium falciparum. The gene, which contains five exons and four introns, encodes a product with a predicted length of 524 amino acids. The amino-terminal segment of the predicted protein contains all of the conserved sequences characteristic of a protein kinase catalytic domain and has a high homology to several protein serine-threonine kinase subfamilies (30-41% amino acid identities). These subfamilies include calcium/calmodulin-dependent protein kinases, calcium-dependent protein kinase, ribosomal S6 protein kinase, cyclic nucleotide-dependent protein kinases, protein kinase C, and the yeast SNF1 subfamily. All of these protein kinases are relatively close in the phylogeny tree and within the kinase catalytic domains have about 35% amino acid identities to each other, suggesting that PfCPK is also in this region of the phylogeny tree. An unusual feature of PfCPK is that its carboxyl-terminal segment displays homology to the EF hand calcium-binding proteins, for example 34% amino acid identity to chicken fast skeletal muscle troponin C and 35% amino acid identity to human calmodulin. Like troponin Cs and calmodulins, PfCPK also contains four EF hand calcium-binding motifs. Furthermore, the four introns in the PfCPK gene are all located in the carboxyl-terminal putative EF hand calcium-binding region (EF hand calcium-binding proteins from higher eukaryotes generally contain multiple introns). This combination of a protein kinase and an EF hand calcium-binding protein in a single polypeptide implies that PfCPK may be directly activated by calcium. Constructs containing the full-length PfCPK cDNA have been expressed in Escherichia coli at a high level to generate a 60-kDa recombinant protein. Compared with similar fractions from control cells, the fraction containing PfCPK recombinant protein exhibited an elevated protein kinase activity which was Ca(2+)-dependent.
...
PMID:Gene structure and expression of an unusual protein kinase from Plasmodium falciparum homologous at its carboxyl terminus with the EF hand calcium-binding proteins. 844 Jul 20

A novel calcium-binding protein (EhCaBP) has been recently identified and characterized from the protozoan parasite Entamoeba histolytica. In order to decipher the function of this protein, a few basic properties were investigated and compared with the ubiquitous Ca(2+)-signal transducing protein calmodulin (CaM). Indirect immunofluorescence and immunoprecipitation analyses using specific antibodies against EhCaBP suggest that it is a soluble cytoplasmic protein with no major post-translational modification. EhCaBP did not stimulate cAMP-phosphodiesterase activity, differentiating it from all known CaMs. Affinity chromatography of [35S]methionine-labelled proteins of E. histolytica trophozoites using EhCaBP-sepharose column showed Ca(2+)-dependent binding of a group of proteins. Radiolabelled proteins from the same extract also bound to CaM-sepharose. However, the proteins bound to the two columns were different as revealed by sodium dodecyl sulphate polyacrylamide gel electrophoresis. At least one of the EhCaBP-binding proteins became phosphorylated as revealed by in vivo phosphorylation analysis. The binding-proteins could not be detected in E. invadens (a species that is pathogenic in reptiles) and E. moshkovskii (which is found in the human gut but is not pathogenic), two species in which EhCaBP-like protein has not been found. Two distinct Ca(2+)-dependent protein kinases, which get activated by EhCaBP and CaM respectively, were detected in E. histolytica. These kinases require different levels of Ca2+ for their maximal activities. Affinity chromatography also showed the binding of protein kinase(s) to EhCaBP in a Ca(2+)-dependent manner. Our data suggest that there may be novel Ca(2+)-signal transduction pathway in E. histolytica mediated by EhCaBP.
...
PMID:Characterization of EhCaBP, a calcium-binding protein of Entamoeba histolytica and its binding proteins. 904 22

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.
...
PMID:Inhibitory effect of regucalcin on Ca2+/calmodulin-dependent protein kinase activity in rat renal cortex cytosol. 945 Jun 68

Calcyphosine is a calcium-binding protein containing four EF-hand domains that is found in several epithelia and in some cells of the central nervous system. In thyroid follicular cells, calcyphosine is synthesized and phosphorylated in response to stimulation by thyrotropin and cAMP agonists. The cDNA coding for dog calcyphosine has been expressed in bacteria under the control of the T7 promoter. Recombinant calcyphosine was purified from crude bacterial lysates by a combination of anion-exchange and hydrophobic interaction chromatography. Phosphorylation assays using the purified catalytic subunit of protein kinase A and the recombinant or the native calcyphosine revealed that, contrary to a previous report, calcyphosine is not significantly phosphorylated by this enzyme in vitro.
...
PMID:Production of dog calcyphosine in bacteria and lack of phosphorylation by the catalytic subunit of protein kinase A in vitro. 945 44

The glial-derived calcium-binding protein S100B can be secreted to act as a neurotrophic factor or a mitogen, stimulating proliferation of glial cells. The extracellular S100B activities rely on the oxidation of the protein cysteine residues (Kligman, D., and Marshak, D. R. (1985) Proc. Natl. Acad. Sci. U. S. A. 82, 7136-7139; Winningham-Major, F., Staecker, J. L., Barger, S. W., Coats, S., and Van Eldik, L. J. (1989) J. Cell Biol. 109, 3063-3071). Here we show that oxidation of the S100B cysteine residues, Cys-68 and Cys-84, induces a conformational change in the protein structure, unmasking a canonical CKII phosphorylation site located within the typical EF-hand calcium-binding site IIbeta. Intrasubunit disulfide-bridged S100B monomer and disulfide-bonded S100B dimer are phosphorylated by the catalytic CKII-alpha subunit on Ser-62 with a Km of 0.5 microM and a Vmax of 10 pmol/min/100 pmol of S100B. Oxidized S100B is the best in vitro CKII-alpha substrate identified so far. Next we show that intrasubunit disulfide-bridged S100B monomer is the most potent S100B species to stimulate [3H]thymidine uptake by C6 glial cells in culture. In addition, the phosphorylated intrasubunit disulfide-bridged S100B monomer retains apparent mitogenic activity toward C6 glial cells, and hence, 32P-labeled S100B should be a useful probe for characterizing the mechanisms by which extracellular oxidized S100B functions. Finally, we show that formation of intrasubunit disulfide-bridged S100B monomer is stimulated by peroxynitrite anion, suggesting that production of mitogenic S100B species could be enhanced in neuropathology associated with peroxynitrite anion production.
...
PMID:Cysteine oxidation in the mitogenic S100B protein leads to changes in phosphorylation by catalytic CKII-alpha subunit. 946 74

The effect of regucalcin, a calcium-binding protein, on Ca2+-and phospholipid-dependent protein kinase (protein kinase C) activity in the cytosol of rat kidney cortex was investigated. With increasing concentrations of Ca2+, phosphatidylserine or dioctanoylglycerol in the reaction mixture, regucalcin (10[-8] M) caused a remarkable inhibition of protein kinase C activity. Regucalcin did not have a significant effect on protein kinase C activity in the presence of phosphatidylserine or dioctanoylglycerol without Ca2+ addition. Moreover, regucalcin significantly inhibited phorbol 12-myristate 13-acetate (PMA)-increased protein kinase C activity. Meanwhile, staurosporine (10[-9] M) caused a significant inhibition of protein kinase C activity. This inhibition was further enhanced by regucalcin addition. Regucalcin itself did not have protein kinase activity in either the presence or the absence of both Ca2+ and phospholipids. These results clearly indicate that regucalcin has an inhibitory effect on protein kinase C activity in the cytosol of rat kidney cortex. This inhibitory effect may be partly due to the regucalcin-induced Ca2+ binding.
...
PMID:Inhibitory effect of calcium-binding protein regucalcin on protein kinase C activity in rat renal cortex cytosol. 958 64


<< Previous 1 2 3 4 5 6 7 Next >>

---