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)

Acidic ribosomal P-proteins form, in all eukaryotic cells, a lateral protuberance, the so-called 'stalk', which is directly involved in translational activity of the ribosomes. In Saccharomyces cerevisiae cells, there are four distinct P-proteins: P1A, P1B, P2A and P2B. In spite of the high level of their structural homology, they are not completely equivalent and may perform different functions. As yet, the protein-protein interactions between yeast P-proteins have not been fully defined. In this paper, the interplay between yeast P-proteins has been investigated by means of a two-hybrid system, chemical cross-linking and gel filtration. The data presented herein show that all P-proteins are able to form homo-oligomeric complexes. By analyzing hetero-interactions, we were able to detect strong interactions between P1A and P2B proteins. Additionally, the pair of P1B and P2A proteins is also able to form a hetero-complex, though at a very low efficiency. All P-proteins are phosphorylated by numerous protein kinases. Using the multifunctional protein kinase CK II, we have shown that incorporation of phosphate into P1A protein can exert its effect on the hetero-oligomerization process, namely by preventing the formation of the hetero-oligomer P1A-P/P2B. These findings are the first to show differences in the oligomerization behavior of the yeast P-proteins; moreover, they emphasize a significant impact of the phosphorylation on the formations of P-protein complex.
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PMID:Oligomerization properties of the acidic ribosomal P-proteins from Saccharomyces cerevisiae: effect of P1A protein phosphorylation on the formation of the P1A-P2B hetero-complex. 1111 39

A protein kinase activity in chorionated oocytes of Rhodnius prolixus phosphorylates in vitro vitellin (VT), the major yolk protein. Phosphatase inhibitors including NaF, sodium vanadate, beta-glycerophosphate and okadaic acid did not alter the protein phosphorylation profile to a visible extent. Among the exogenous protein substrates tested, casein was readily phosphorylated, but histones were not. Several different protein kinase activators, including cAMP, Ca2+ plus calmodulin, Ca2+ plus diolein and phosphatidylserine, were added to the reaction media but spermidine was the only effective one, inducing a 2-fold increase in the phosphorylation of VT. A strong inhibition was obtained with nanomolar levels of heparin. The enzyme could also accept GTP as the phosphate donor instead of ATP. These properties identify the major protein kinase activity as a type II casein kinase (CK II). The pH dependence and the effects of mono- and divalent cations on VT phosphorylation were also studied. Gel filtration revealed only one peak of protein kinase activity, with a molecular mass of 170 K, similar to values previously reported in the literature for CK IIs from other organisms.
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PMID:Protein phosphorylation in Rhodnius prolixus oocytes: identification of a type II casein kinase. 1144 84

Eukaryotic translation initiation factor 5 (eIF5) interacts with the 40S initiation complex (40S*eIF3*AUG*Met-tRNA(f)*eIF2*GTP) and, acting as a GTPase activating protein, promotes the hydrolysis of bound GTP. We isolated a protein kinase from rabbit reticulocyte lysates on the basis of its ability to phosphorylate purified bacterially expressed recombinant rat eIF5. Physical, biochemical and antigenic properties of this kinase identify it as casein kinase II (CK II). Mass spectrometric analysis of maximally in vitro phosphorylated eIF5 localized the major phosphorylation sites at Ser-387 and Ser-388 near the C-terminus of eIF5. These serine residues are embedded within a cluster of acidic amino acid residues and account for nearly 90% of the total in vitro eIF5 phosphorylation. A minor phosphorylation site at Ser-174 was also observed. Alanine substitution mutagenesis at Ser-387 and Ser-388 of eIF5 abolishes phosphorylation by the purified kinase as well as by crude reticulocyte lysates. The same mutations also abolish phosphorylation of eIF5 when transfected into mammalian cells suggesting that CK II phosphorylates eIF5 at these two serine residues in vivo as well.
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PMID:Phosphorylation of mammalian translation initiation factor 5 (eIF5) in vitro and in vivo. 1186 6

Marburg virus, a filovirus, contains only one transmembrane protein (GP) which is responsible for receptor recognition on target cells. GP, a type I membrane protein of approximately 220 kDa, is acylated and highly glycosylated carrying N- and O-linked sugar side chains. GP is transported through the exocytotic pathway toward the plasma membrane where budding of virions takes place. In the trans-Golgi network, GP is proteolytically activated by the prohormone convertase furin into two subunits GP(1) and GP(2). In the present paper, we provide evidence that GP undergoes an additional posttranslational modification; it is phosphorylated at its ectodomain. Phosphorylation takes place at serine residues between amino acid 260 and 273. The respective serines are located in conserved recognition sites for luminal protein kinases (protein kinase CK II and Golgi casein kinase). Consistent with this data, it was found that GP was phosphorylated in the Golgi apparatus of the expressing HeLa cells before cleavage of the molecule. GP is the first example of a viral glycoprotein with a phosphorylated ectodomain.
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PMID:The Marburg virus surface protein GP is phosphorylated at its ectodomain. 1203 62

In this study we show that Vitellin (VT) phosphorylation in chorionated oocytes of Rhodnius prolixus is completely inhibited by heparin (10 microg/ml), a classical casein kinase II (CK II) inhibitor. VT phosphorylation is not affected by modulators of cyclic nucleotide-dependent protein kinases such as c-AMP (10 microM), H-8 (1 microM) and H-89 (0.1 microM). We have obtained a 3000-fold VT-free enriched preparation of CK II. Autophosphorylation of this enzyme preparation in the presence of (32)P-ATP demonstrated that it lacks any endogenous substrates. Rhodnius CK II is strongly inhibited by heparin (Ki = 9 nM) and uses ATP (Km = 36 microM) or GTP (Km = 86 microM) as phosphate donors. Incubation of VT with purified Rhodnius CK II and (32)P-ATP led to the incorporation of 2 mols of phosphate/mol VT. However, the total number of phosphorylation sites available can be altered by previous incubation of VT with alkaline phosphatase. These data show that an insect yolk protein contain phosphorylation sites for a cyclic nucleotide-independent protein kinase such as CK II.
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PMID:Cyclic nucleotide-independent phosphorylation of vitellin by casein kinase II purified from Rhodnius prolixus oocytes. 1211 Feb 92

Protein kinases play a central role in controlling the cellular metabolism of living organisms. A protein kinase was purified from etiolated oat seedlings by several steps of ion-exchange and affinity chromatographies. The kinase was a 150-kDa tetrameric protein and composed of three subunits of 34, 37, and 40 kDa proteins. The 34 and 40 kDa proteins had ATP binding sites, suggesting that they are catalytic subunits and that the 37-kDa protein is a regulatory subunit. In the in vitro phosphorylation of a crude oat cell extract, it intensively phosphorylated a serine residue of a 110-kDa protein. The 110-kDa protein was tentatively identified as a DNA topoisomerase I, based on an amino acid sequence homology. Phosphorylation of the 110-kDa protein by the kinase required ATP or GTP as a phosphoryl group donor. The kinase activity was inhibited by 50% at a concentration of 0.05 microg/ml heparin. These results, therefore, indicate that the purified kinase is a CK II protein kinase and may be involved in the regulation of DNA topoisomerase I activity.
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PMID:Characterization of a CK II protein kinase from etiolated oat seedlings. 1224 54

Phosphoprotein P of rinderpest virus (RPV), when expressed in E. coli, is present in the unphosphorylated form. Bacterially expressed P protein was phosphorylated by a eukaryotic cellular extract, and casein kinase II (CK II) was identified as the cellular kinase involved in phosphorylation. In vitro phosphorylation of P-deletion mutants identified the N terminus as a phosphorylation domain. In vivo phosphorylation of single or multiple serine mutants of P protein identified serine residues at 49, 88 and 151 as phospho-acceptor residues. The role of P protein phosphorylation in virus replication/transcription was evaluated using the RPV minigenome system and replication/transcription of a reporter gene in vivo. P protein phosphorylation was shown to be essential for in vivo replication/transcription since phosphorylation-null mutants do not support expression of a reporter gene. Transfection of increased amounts of phosphorylation-null mutant did not support minigenome replication/transcription in vivo.
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PMID:Cellular casein kinase II-mediated phosphorylation of rinderpest virus P protein is a prerequisite for its role in replication/transcription of the genome. 1499 54

In rat erythrocytes, the regulation of Na+/Mg2+ antiport by protein kinases (PKs), protein phosphatases (PPs), intracellular Mg2+, ATP and Cl- was investigated. In untreated erythrocytes, Na+/Mg2+ antiport was slightly inhibited by the PK inhibitor staurosporine, slightly stimulated by the PP inhibitor calyculin A and strongly stimulated by vanadate. PMA stimulated Na+/Mg2+ antiport. This effect was completely inhibited by staurosporine and partially inhibited by the PKC inhibitors Ro-31-8425 and BIM I. Participation of other PKs such as PKA, the MAPK cascade, PTK, CK I, CK II, CAM II-K, PI 3-K, and MLCK was excluded by use of inhibitors. Na+/Mg2+ antiport in rat erythrocytes can thus be stimulated by PKCalpha. In non-Mg2+ -loaded erythrocytes, ATP depletion reduced Mg2+ efflux and PMA stimulation in NaCl medium. A drastic activation of Na+/Mg2+ antiport was induced by Mg2+ loading which was not further stimulated by PMA. Staurosporine, Ro-31-8425, BIM I and calyculin A did not inhibit Na+/Mg2+ antiport of Mg2+ -loaded cells. Obviously, at high [Mg2+]i Na+/Mg2+ antiport is maximally stimulated. PKCalpha or PPs are not involved in stimulation by intracellular Mg2+. ATP depletion of Mg2+ -loaded erythrocytes reduced Mg2+ efflux and the affinity of Mg2+ binding sites of the Na+/Mg2+ antiporter to Mg2+. In non-Mg2+ -loaded erythrocytes Na+/Mg2+ antiport essentially depends on Cl-. Mg2+ -loaded erythrocytes were less sensitive to the activation of Na+/Mg2+ antiport by [Cl-]i.
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PMID:Regulation of Na+/Mg2+ antiport in rat erythrocytes. 1532 47

In studies of the function of neurofilaments in the squid giant axon we showed that isolated neurofilament preparations from axoplasm are associated with high levels of casein kinase-like activity. To determine the role of these kinases in phosphorylation of neurofilament proteins, we isolated two kinases from squid brain which are also found in axoplasm, CK I and CK II. The CKI is similar to this axonal neurofilament-associated CKI-like kinase activity. CK I displayed a high specificity for the squid high molecular weight (NF220) and rat high molecular weight (NF-H) neurofilament proteins relative to alpha-casein, phosvitin, and middle (NF-M) and low (NF-L) rat neurofilament proteins. The brain CKII, with activity similar to that found in axoplasm, but not associated with neurofilaments, poorly phosphorylated NF220 and NF-H, while demonstrating similar affinities, relative to CK I, for NF-M, NF-L, alpha-casein, and phosvitin. The high affinity of squid neuronal CKI for squid NF220 and rat NF-H and its association with axonal neurofilaments suggest that this kinase may have a specific role in neurofilament phosphorylation essential for interaction with other cytoskeletal elements in the axon.
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PMID:Casein kinases I and II from squid brain exhibit selective neurofilament phosphorylation. 1991 98

The identification of protein kinase targets remains a significant bottleneck for our understanding of signal transduction in normal and diseased cellular states. Kinases recognize their substrates in part through sequence motifs on substrate proteins, which, to date, have most effectively been elucidated using combinatorial peptide library approaches. Here, we present and demonstrate the ProPeL method for easy and accurate discovery of kinase specificity motifs through the use of native bacterial proteomes that serve as in vivo libraries for thousands of simultaneous phosphorylation reactions. Using recombinant kinases expressed in E. coli followed by mass spectrometry, the approach accurately recapitulated the well-established motif preferences of human basophilic (Protein Kinase A) and acidophilic (Casein Kinase II) kinases. These motifs, derived for PKA and CK II using only bacterial sequence data, were then further validated by utilizing them in conjunction with the scan-x software program to computationally predict known human phosphorylation sites with high confidence.
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PMID:Using bacteria to determine protein kinase specificity and predict target substrates. 2330 Jul 58


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