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)

The amino-terminal domain of the large subunit of herpes simplex virus type 2 (HSV-2) ribonucleotide reductase (ICP10) has protein kinase (PK) activity and properties similar to those of growth factor receptor kinases which can be activated to transforming potential. DNA sequences that encode the PK domain cause neoplastic transformation of immortalized cells. The studies described in this report used a spontaneous mutant (ts5-152) temperature-sensitive for the synthesis of ICP10 and the previously described ICP10 expression vectors to study the role of ICP10 expression in HSV-2 growth and neoplastic potential. The titres of the ts5-152 mutant are 1000-fold lower at 39 degrees C compared to 34 degrees C after 12 h post-infection. The efficiency of plaquing is 0.003. The growth defect at 39 degrees C correlates with decreased ICP10 synthesis. Sequence analysis of the PK domain of the ts5-152 ICP10 gene identified a pair of frameshift mutations resulting in a 19 amino acid residue substitution at positions 275 to 293 and a downstream single base pair mutation causing a substitution at position 309. Cloning of the mutant ICP10 gene from ts5-152 into a wild-type HSV-2 isolate resulted in a recombinant (859/152) with growth properties and rates of ICP10 synthesis at 39 degrees C similar to those of ts5-152. Cells transformed with u.v.-inactivated ts5-152, or the recombinant 859/152, have significantly decreased cloning efficiency in agarose at 39 degrees C, but only during the first 250 post-transfer population doublings. Anchorage-independent growth was observed in cells transfected with expression vectors pJW17 or pJW32 that express ICP10 or its PK domain, respectively. Cells transfected with the frameshift mutant pJW21 or the ICP10 carboxy-terminal vector pJW31 did not form clones in agarose.
...
PMID:Expression of the large subunit of herpes simplex virus type 2 ribonucleotide reductase (ICP10) is required for virus growth and neoplastic transformation. 131 43

We report on a protein kinase function encoded by the unique N terminus of the herpes simplex virus type 1 (HSV-1) ribonucleotide reductase large subunit (R1). R1 expressed in Escherichia coli exhibited autophosphorylation activity in a reaction which depended on the presence of the unique N terminus. When the N terminus was separately expressed in E. coli and partially purified, a similar autophosphorylation reaction was observed. Importantly, transphosphorylation of histones and of proteins in HSV-1-infected cell extracts was also observed with purified R1 and with truncated R1 mutants in which most of the N terminus was deleted. Ion-exchange chromatography was used to separate the autophosphorylating activity of the N terminus from the transphosphorylating activity of an E. coli contaminant protein kinase. We propose a putative function for this activity of the HSV-1 R1 N terminus during the immediate-early phase of virus replication.
...
PMID:An autophosphorylating but not transphosphorylating activity is associated with the unique N terminus of the herpes simplex virus type 1 ribonucleotide reductase large subunit. 133 36

The 140-kDa ribonucleotide reductase (RR1) protein of herpes simplex virus type 2 (HSV-2) functions as the large subunit of virus-specified RR1 and exhibits an intrinsic protein kinase (PK) activity at its unique NH2-terminal region. The N-terminal half of RR1 contains the protein and DNA functions of the morphological transforming region III (mtrIII) of HSV-2. In the present study, we have expressed a number of truncated RR1 derivatives in a mammalian expression vector containing NH2-terminal RR1 gene fragments and amber mutants generated by site-specific mutagenesis. These derivatives, synthesized in transient expression assays, were used as test antigens to localize the epitopes of a panel of HSV-2 RR1-reactive monoclonal antibodies and to fine-map the PK catalytic domain. Our data show that the epitope for HSV-2-specific monoclonal antibody 6A-6 is located in a region of RR1 protein spanning aa 72-350. The epitopes for cross-reactive antibodies to HSV RR1, i.e., 48S and 51S, are formed predominantly by a stretch of amino acid residues specified by aa 350-376 of the RR1 molecule. The 6A-6 antibody utilized in conjunction with the RR1 amber mutants has allowed us to define a 278 aa domain within the NH2-terminal half of the 140-kDa RR1 (aa 72-350) that is sufficient for PK activity.
...
PMID:Localization of the antigenic sites and intrinsic protein kinase domain within a 300 amino acid segment of the ribonucleotide reductase large subunit from herpes simplex virus type 2. 137 Oct 28

The 1.3-kilobase (kb) Pst I DNA fragment C (Pst I-C) of herpes simplex virus type 2 (HSV-2) morphological transforming region III (mtrIII; map unit 0.562-0.570) encodes part of the N-terminal half of the large subunit of ribonucleotide reductase (RR1; amino acid residues 71-502) and induces the neoplastic transformation of immortalized cell lines. To assess directly the role of these RR1 protein sequences in cell transformation, the Pst I-C fragment was cloned in an expression vector (p91023) containing an adenovirus-simian virus 40 promoter-enhancer to generate recombinant plasmid p9-C. Expression of a protein domain (approximately 65 kDa) was observed in p9-C-transfected COS-7 and Rat2 cells but not in those transfected with plasmid pHC-14 (Pst I-C in a promoterless vector). In Rat2 cells, p9-C induced highly transformed foci at an elevated frequency compared with that of pHC-14. Introduction of translation termination (TAG) condons within the RR1 coding sequence and within all three reading frames inactivated RR1 protein expression from p9-C and reduced its transforming activity to the level seen with the standard pHC-14 construct. Wild-type p9-C specified a protein kinase capable of autophosphorylation. Computer-assisted analysis further revealed significant similarity between regions of mtrIII-specific RR1 and amino acid patterns conserved within the proinsulin precursor family and DNA transposition proteins. These results identify a distinct domain of the HSV-2 RR1 protein involved in the induction of enhanced malignant transformation. In addition, the data indicate that the mtrIII DNA itself can induce basal-level transformation in the absence of protein expression.
...
PMID:Enhanced malignant transformation induced by expression of a distinct protein domain of ribonucleotide reductase large subunit from herpes simplex virus type 2. 165 64

We compared deoxyadenosine (AdR)- and cyclic AMP (cAMP)-induced cell cycle arrest and cytotoxicity in wild type and mutant S49 cells to determine whether they resulted from the same or different mechanisms. Cyclic AMP and deoxyadenosine are synergistic rather than additive in cytotoxicity assays, suggesting different mechanisms of toxicity. Although cyclic AMP causes cell death after 72 h, in concentrations sufficient to result in cell cycle arrest it is reversible with virtually no cytotoxicity for at least 24 h, whereas AdR-induced cell cycle arrest is lethal and irreversible. AdR-induced G1 cell cycle arrest results in diminished ribonucleotide reductase activity but the kinetics of this inhibition differ from cyclic AMP-induced cell cycle arrest. Cyclic AMP arrest and cytotoxicity depend on cyclic AMP-dependent protein kinase (PKA) activity, whereas AdR toxicity does not differ between cell lines with or without PKA activity. Furthermore, deoxycytidine prevents AdR cell cycle arrest and cytotoxicity but has no effect on cyclic AMP G1 arrest. Finally, comparison of cytofluorographic patterns of G1-arrested cells suggests that the AdR block is later in G1 than cyclic AMP-induced cell cycle arrest. In summary, these data show that while the mechanisms of cell cycle arrest and cytotoxicity of cyclic AMP and deoxyadenosine are uncertain, they do appear to involve different pathways.
...
PMID:Deoxyadenosine- and cyclic AMP-induced cell cycle arrest and cytotoxicity. 165 3

The amino-terminal domain of the large subunit of herpes simplex virus type 2 ribonucleotide reductase (ICP10) contains a serine/threonine-specific protein kinase that has characteristics of a growth factor receptor (Chung, T. D., Wymer, J. P., Smith, C. C., Kulka, M., and Aurelian, L. (1989) J. Virol. 63, 3389-3398; Chung, T. D., Wymer, J. P., Kulka, M. Smith, C. C., and Aurelian, L. (1990) Virology 179, 168-178). To characterize this protein kinase (PK) domain further we constructed a bacterial expression vector (pJL11) containing DNA sequences encoding ICP10 amino acid residues 1-445. Bacteria containing pJL11 were induced to express a 29-kDa protein (designated pp29la1) that represents a truncated portion of the ICP10-PK domain (includes PK catalytic motifs I-V) as demonstrated by immunoprecipitation with antibodies that recognize different antigenic domains, competition studies with extracts of ICP10-positive eukaryotic cells, and peptide mapping.pp29la1 has autophosphorylating and transphosphorylating activity for calmodulin. The enzyme is activated by Mn2+ but not by Mg2+ ions, and autophosphorylation is inhibited by histone. It differs from the authentic ICP10-PK in that phosphorylation is specific only for threonine.
...
PMID:A truncated protein kinase domain of the large subunit of herpes simplex virus type 2 ribonucleotide reductase (ICP10) expressed in Escherichia coli. 165 40

Herpes simplex virus (HSV) ribonucleotide reductase is formed by the association of two distinct dimeric subunits, R1 and R2. Attempts to purify either the HSV holoenzyme or its R1 subunit in their active form have been unsuccessful until now. The C terminus of the R2 protein being involved in the association with R1, the synthetic nonapeptide corresponding to this terminus, impedes the formation of the holoenzyme by competing with R2 for a critical site on R1. Based upon these observations, we developed an affinity chromatographic procedure to purify the R1 protein from HSV-1-infected baby hamster kidney cells. Specific binding of R1 to an affinity column made by linking the peptide HSV R2-(326-337) to Affi-Gel 10, followed by specific elution with an excess of an analogous peptide exhibiting a higher affinity for R1 yielded, in a single step, highly purified R1 protein. The purified R1 preparations contained approximately 95% of intact R1, the remaining 5% consisting of two R1 copurifying proteolytic breakdown products. The purified R1 protein exhibited a high reductase specific activity when mixed with an excess of the R2 subunit. Moreover, in vitro kinase assays revealed that the purified R1 protein of HSV-1 possesses an autophosphorylating activity also able to phosphorylate alpha-casein and histone II-S. The intrinsic protein kinase activity of HSV R1 is associated with its unique N-terminal domain which is absent from all other reductase subunits 1 and contains consensus motifs found in Ser/Thr protein kinases. A preliminary characterization of the kinase activity of the R1 protein of HSV-1 ribonucleotide reductase is presented.
...
PMID:Affinity purification of active subunit 1 of herpes simplex virus type 1 ribonucleotide reductase exhibiting a protein kinase activity. 185 53

Ribonucleotide reductase activity in S49 T lymphoma cells is cell cycle regulated by de novo protein synthesis of the M2 subunit. There is maximal enzyme activity in S and G2/M phase with low activity and low concentrations of the M2 subunit in G1 phase. Pharmacologic concentrations of cyclic AMP arrest S49 cells in the G1 phase of the cell cycle. We investigated the effect of cyclic AMP on M2 messenger RNA concentrations using RNA from exponentially growing and elutriated, cell cycle-enriched populations. To discern whether cyclic AMP-induced G1 arrest was associated with low concentrations of M2-specific messenger RNA, we probed blots with a full-length cDNA for M2. Cell cycle variation in M2 messenger RNA concentrations was similar in wild-type, hydroxyurea-resistant cells with amplified M2 activity, and cyclic AMP-dependent protein kinase-deficient cell lines. All lines had low amounts of M2-specific mRNA in early G1, an increase at the late G1/early S phase interface, a decrease in mid S phase, and another increase in late S phase that continued through G2/M. These concentrations did not directly correlate with enzyme activity, suggesting other regulatory effects might participate in determining ribonucleotide reductase activity. Cyclic AMP exposure appeared to induce cell cycle arrest in early G1 with low M2-specific messenger RNA concentration. This effect reversed upon washout of the cyclic AMP and was dependent on functional cyclic AMP-dependent protein kinase (PKA). These results suggest that cyclic AMP arrests S49 mouse T lymphoma cells in early G1 prior to transcriptional activation of the M2 gene.
...
PMID:Effect of cyclic AMP on the cell cycle regulation of ribonucleotide reductase M2 subunit messenger RNA concentrations in wild-type and mutant S49 T lymphoma cells. 215 14

The amino-terminal domain of the large subunit of herpes simplex virus type 2 (HSV-2) ribonucleotide reductase (ICP10) was previously shown to possess protein kinase (PK) activity that localizes to the cytosolic, cytoskeletal, and plasma membrane fractions. Further studies of the PK domain using computer-assisted sequence analysis have identified a single transmembrane segment and fatty acid incorporation findings indicate that ICP10 is myristylated. Myristylation does not depend on a viral enzyme, since myristic acid is incorporated into ICP10 precipitated from cells transfected with an ICP10 expression vector. It is also incorporated into the 57-kDa protein expressed by the amino-terminal PK expression vector. The myristyl moiety is linked through an amide bond. The basic protein polylysine stimulates the kinase activity and alters its divalent cation requirements resulting in 20- to 40-fold stimulation in the presence of 0.1 mM Mn2+. The PK activity is inhibited by antibody to synthetic peptides corresponding to residues 355-369 and 13-26, respectively, located within, and amino-terminal to, the predicted PK catalytic domain.
...
PMID:Myristylation and polylysine-mediated activation of the protein kinase domain of the large subunit of herpes simplex virus type 2 ribonucleotide reductase (ICP10). 217 Dec 4

Cyclic AMP arrests T lymphocytes in the G1 phase of the cell cycle, and prolonged exposure results in cytolysis. Both of these effects require cyclic AMP-dependent protein kinase. We recently observed that some S49 mouse T lymphoma cell lines selected for hydroxyurea resistance were not arrested in G1 by cyclic AMP. Further analysis revealed that these cell lines were cyclic AMP-dependent protein kinase deficient, and conversely, other cyclic AMP-dependent protein kinase deficient cell lines not selected for hydroxyurea resistance were two- to threefold more hydroxyurea resistant. However, hydroxyurea is a specific inhibitor of ribonucleotide reductase and does not inhibit this kinase. We subsequently showed that cyclic AMP-dependent protein kinase will phosphorylate the M2 but not the M1 subunit of ribonucleotide reductase in vitro, and this phosphorylation will diminish CDP reductase activity. In vivo phosphorylation of M2 occurred under conditions similar to those that generate cell cycle arrest. We conclude that the M2 subunit of ribonucleotide reductase can be a target of cyclic AMP-dependent protein kinase. The phosphorylated enzyme has diminished activity, and this may play a role in cyclic AMP-induced lymphocyte cell cycle arrest.
...
PMID:M2 subunit of ribonucleotide reductase is a target of cyclic AMP-dependent protein kinase. 253 34


1 2 3 4 5 6 7 8 Next >>

---