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)

Phosphoenolpyruvate PyrP carboxylase (PyrPC) and PyrPC kinase were copurified from dark-adapted leaves of the common ice plant Mesembryanthemum crystallinum L. with crassulacean-acid metabolism (CAM). Purification by (NH4)2SO4 fractionation, chromatography on Fractogel-DEAE and hydroxylapatite resulted in a PyrPC preparation with a specific activity of 23-25 U/mg protein and a protein kinase activity of 255 mumol Pi.mol-1 PyrPC.s-1. After in vitro phosphorylation, the most prominently phosphorylated polypeptide was identified as PyrPC by immunoblotting and sequencing. Phosphorylation of PyrPC in vitro by incubation with 400 microM MgATP decreased its sensitivity towards malate. When purified in the absence of the protease inhibitor chymostatin, PyrPC lost an N-terminal sequence of 128 amino acids. Although the carboxylation reaction was unaffected, the truncated PyrPC could neither be phosphorylated in vitro nor inhibited by malate. This result and data obtained by limited proteolysis concur with the hypothesis [Jiao, J.A. & Chollet, R. (1989) Arch. Biochem. Biophys. 283, 300-305] that Ser11 is the phosphorylation site of the CAM PyrPC of M. crystallinum. At pH 7.0, the Km for ATP of the protein kinase was 25 microM; phosphorylation of PyrPC was maximal after 30 min at pH 7.0. The kinase showed also activity with histone III-S but not with dephosphorylated casein. It was inhibited by malate. The results show, that reversible protein phosphorylation is an important factor in the regulation of PyrPC in the facultative CAM plant M. crystallinum, similar to C4 and constitutive CAM plants.
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PMID:Regulatory protein phosphorylation of phosphoenolpyruvate carboxylase in the facultative crassulacean-acid-metabolism plant Mesembryanthemum crystallinum L. 139 23

Mitotic spindles isolated from prometaphase-arrested mammalian cells contain associated protein kinases that are extracted by high salt treatment. Their fractionation by ion-exchange chromatography reveals three major peaks of protein kinase activity that phosphorylate brain microtubule-associated proteins and differ in their substrate specificity. One of them has been identified as a casein kinaseII-like enzyme. A mitotic spindle-associated 325 kDa protein related to brain MAP1B is a major substrate for this casein kinase II-like enzyme. Another mitotic spindle protein kinase has been tentatively identified as a proline-directed protein kinase.
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PMID:Protein kinases associated with isolated mitotic spindles from mammalian cells: identification of a casein kinase II-like enzyme. 140 49

Casein kinase I (CKI) is a class of protein kinases ubiquitous to all eukaryotic cells. Recently, cDNA clones encoding several bovine CKI isoforms have been sequenced that show high sequence identity to the HRR25 gene product of the budding yeast Saccharomyces cerevisiae; HRR25 is required for normal cellular growth, nuclear segregation, DNA repair, and meiosis. We have raised polyclonal antibodies to a human erythroid 34-kDa CKI and have sequenced a portion of this kinase. The amino acid sequence identifies the CKI as the alpha-CKI isoform, which is 62% identical to the HRR25 protein kinase. By use of immunofluorescence, the alpha-CKI has been localized to vesicular cytosolic structures and to the centrosome in interphase cells. As cells progress into mitosis, centrospheric staining increases and, in mitosis, alpha-CKI associates with kinetochore fibers. This localization suggests that alpha-CKI, like HRR25, plays a role in the segregation of chromosomes during mitosis and may be cell cycle-regulated both in humans and in yeast.
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PMID:Cell cycle-dependent localization of casein kinase I to mitotic spindles. 140 56

The hypothesis that casein kinase II (CKII) is a microtubule-associated protein kinase was investigated using a neuronal cell line and bovine brain. Heparin, an inhibitor of CKII, inhibited the phosphorylation of a PC12 cytosolic protein whose molecular weight was similar to that of beta-tubulin. Partially purified PC12 CKII was immunoreactive to an antibody directed against bovine CKII and was able to phosphorylate purified beta-tubulin in a heparin-inhibitable manner when the concentration of tubulin was less than 50 micrograms/ml. To better determine if CKII is a microtubule-associated protein kinase, bovine brain tubulin was chromatographed on FPLC Mono Q and phosphocellulose columns. Several tubulin casein kinase (TCK) activities were apparent. All TCK activities phosphorylated tubulin and casein, but none was able to phosphorylate the CKII-specific synthetic peptide RRREEETEEE. One of these TCK fractions was immunoreactive to the antibody directed against CKII, and this antibody labeled a 50-kDa molecular mass band that had a molecular mass distinctly different from those of the subunits of CKII. Thus, we suggest that a CKII-like protein, but not CKII, might be a microtubule-associated protein.
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PMID:A casein kinase-like kinase phosphorylates beta-tubulin and may be a microtubule-associated protein. 143 92

The absence of casein kinase 2 on blots of temporal cortex extracts from Alzheimer's disease patients (ADP) was shown using antiserum to casein kinase 2. Casein kinase 2 activity towards endogenous substrates and casein is 2-5 times less in ADP brain in comparison to normal controls. The fractions of heparin-binding proteins, containing protein substrates for phosphorylation, were isolated from temporal cortex of ADP and normal controls. The total amount of heparin-binding proteins from ADP brains is less than from control brains, and the polypeptide composition of these fractions is much more poop.
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PMID:[Cytoplasmic casein kinase 2 and its substrate proteins in the brain in Alzheimer's disease]. 144 27

A Dictyostelium discoideum cDNA encoding an alpha-type subunit of casein kinase II was isolated, and its cDNA was used to study developmental expression of casein kinase II during the Dictyostelium life cycle. The 1.3-kb cDNA insert contained an open reading frame of 337 amino acids (M(r) 39,900). The deduced amino acid sequence has high homology with those of casein kinase II alpha subunits from other species. Genomic Southern blot analysis suggested that there is a single gene encoding casein kinase II alpha subunit in D. discoideum. Northern (RNA) blot analysis showed that the casein kinase II alpha-subunit gene is expressed constitutively as a 1.9-kb mRNA throughout vegetative growth and multicellular development. Casein kinase purified from normal vegetative cells contained a major protein band of approximately 36 kDa, which was recognized by antisera raised against rat testis casein kinase II. Comparison of the in vitro transcription/translation product of the alpha-subunit cDNA clone and the purified 36-kDa protein by partial proteolysis indicated that the isolated cDNA clone encodes the Dictyostelium casein kinase II alpha subunit. No protein corresponding to a beta subunit was detected in purified casein kinase. Immunoblot analysis using anti-rat casein kinase II sera showed that the alpha subunit of casein kinase II is expressed constitutively like its mRNA during the life cycle of D. discoideum. Casein kinase II activity measured by using a specific peptide substrate paralleled the level of alpha subunit detected by immunoblotting during the life cycle, with a maximum variation of approximately 2-fold. We were unable to obtain disruptants of the casein kinase II alpha gene, suggesting that there is a single casein kinase II alpha gene, which is essential for vegetative growth of D. discoideum.
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PMID:Molecular cloning of casein kinase II alpha subunit from Dictyostelium discoideum and its expression in the life cycle. 144

Vaccinia virus open reading frame B1R was expressed in E. coli and shown to encode a serine/threonine protein kinase which phosphorylated casein and calf thymus histones in vitro. A polyclonal rabbit antiserum was raised against a TrpE-B1R bacterial fusion protein and used to characterize the B1R gene product. Immunoprecipitation and immunoblotting analyses detected a 34-kDa polypeptide that was synthesized early during vaccinia virus infection and which was apparently stable since it was easily detectable 18 hr postinfection. Immunofluorescence demonstrated that this protein localizes in cytoplasmic virus factories, the sites of virus DNA replication. Immunoblotting of vaccinia virions showed that the enzyme is packaged into virus particles.
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PMID:Vaccinia virus gene B1R encodes a 34-kDa serine/threonine protein kinase that localizes in cytoplasmic factories and is packaged into virions. 144 24

During the course of characterizing polymerase chain reaction products corresponding to protein kinases of a higher plant, Arabidopsis thaliana, we found a DNA fragment that potentially codes for a polypeptide with mosaic sequences of two classes of protein kinases, a tyrosine-specific and a serine/threonine-specific one. Overlapping complementary DNA (cDNA) clones coinciding with this fragment were isolated from an A. thaliana cDNA library. From their sequence analyses a protein kinase was predicted composed of 410 amino acid residues (APK1, Arabidopsis protein kinase 1), in which the kinase domain was flanked by short non-kinase domains. Upon expression of APK1 in Escherichia coli cells, several bacterial proteins became reactive with anti-phosphotyrosine antibody but not with the same antibody preincubated with phosphotyrosine, convincing us that APK1 phosphorylated tyrosine residues. APK1 purified from an over-producing E. coli strain showed serine/threonine kinase activity, and no tyrosine kinase activity, towards APK1 itself, casein, enolase, and myosin light chains. APK1 was thus concluded to be a novel type of protein kinase, which could phosphorylate tyrosine, serine, and threonine residues, though tyrosine phosphorylation seemed to occur only on limited substrates. Since the structure of the APK1 N-terminal portion was indicative of N-myristoylation, APK1 might associate with membranes and thereby contribute to signal transduction. The A. thaliana genome contained two APK1 genes close to each other (APK1a and APK1b).
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PMID:Novel protein kinase of Arabidopsis thaliana (APK1) that phosphorylates tyrosine, serine and threonine. 145 Mar 80

1. A protein kinase type II was purified from calf thymus chromatin using ammonium sulphate fractionation, ion exchange chromatography on DEAE and phosphocellulose and affinity chromatography on phosvitin- and casein-sepharose columns. 2. The enzyme moves as a single band in non-denaturing gel electrophoresis at pH 8.3, which coincides with the enzyme activity assayed on gel slices. 3. Sodium dodecyl sulphate gel electrophoresis shows three separate polypeptide chains having M(r) of 40,000, 38,000 and 25,000, respectively. The native M(r) was about 130,000, as measured by HPLC on Superose 12 column, suggesting a subunit structure of alpha, alpha', beta 2 type. The enzyme incubated with [gamma 32P]ATP or [gamma 32P]GTP as phosphoryl donors undergoes autophosphorylation in the M(r) = 25,000 subunit. 4. The enzyme phosphorylates casein (Km = 7 microM) and phosvitin (Km = 5 microM) but not histones and was strongly deactivated by Zn2+ ions (I50 = 0.05 mM) and heparin (I50 = 0.1 micrograms/ml). 5. The enzyme seems to be the major phosphorylating system present in the 0.35 M NaCl chromatin extract of calf thymus. The RNA polymerase II from calf thymus and RNA polymerase from E. coli are both phosphorylated by protein kinase NII. The effect of phosphorylation, which causes a remarkable increase of DNA transcription rate, was studied in vitro and extensively discussed.
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PMID:Protein kinase NII from calf thymus chromatin. Isolation, characterization and some functional properties. 145 14

A simplified procedure for casein kinase 2 purification from bovine brain is described. The purification procedure consists of two affinity chromatography steps, using heparin and polyethylenimine immobilized on a synthetic matrix (Toyopearl 650M). The adsorption and elution conditions for each column were optimized, resulting in a simple elution protocol for each column. A stable, highly purified casein kinase 2 preparation was obtained in 4 h using this procedure. Polyethylenimine was shown to stimulate the casein kinase 2 activity using exogeneous substrates (casein, calmodulin, MAP2, and tau) but not the enzyme's autophosphorylation activity. The polyethylenimine stimulation could be overcome by applying a mass excess of the casein kinase 2 inhibitor, heparin.
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PMID:Brain casein kinase 2: affinity purification procedure using immobilized polyethylenimine. 145 49


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