Ribosomal protein S2/Sa kinase purified from HeLa cells infected with vaccinia virus corresponds to the B1R protein kinase and phosphorylates in vitro the viral ssDNA-binding protein

Beaud, Georges; Sharif, A.; Topa-Massé, Agata; Leader, David P.

doi:10.1099/0022-1317-75-2-283

Cited by 26 publications

(27 citation statements)

References 28 publications

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“…The relevance of this observation to the chemopreventive ability of celecoxib remains to be determined. Other markers targeted for altered expression by celecoxib included a multifunctional protein, nucleolin, implicated in ribosomal biogenesis, transcriptional repression, cell survival, and proliferation (51); Annexin, involved in calcium signaling and membrane dynamics (52); SET, a potential oncoprotein and phosphatase inhibitor (53); and S2/Sa, a ribosomal protein kinase (54).…”

Section: Discussionmentioning

confidence: 99%

Proteomic Profiling Identifies Cyclooxygenase-2-Independent Global Proteomic Changes by Celecoxib in Colorectal Cancer Cells

Lou

Xiao²,

Stauffer³

et al. 2006

Cancer Epidemiology, Biomarkers &Amp; Prevention

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Celecoxib, a selective inhibitor of the enzyme cyclooxygenase-2 (COX-2), has been shown to be a promising chemoprevention agent. The chemopreventive efficacy of celecoxib is believed to be a consequence of its COX-2-dependent and COX-2-independent effects on a variety of cellular processes including proliferation, apoptosis, angiogenesis, and immunosurveillance. In an attempt to identify proteomic markers modulated by celecoxib that are independent of its inhibitory effect on COX-2, the colorectal cancer cell line HCT-116, a nonexpresser of COX-2, was treated with celecoxib. We used the powerful, state-of-the-art two-dimensional difference gel electrophoresis technology coupled with mass spectrometric sequencing to compare global proteomic profiles of HCT-116 cells before and after treatment with celecoxib. Among the differentially expressed proteins identified following celecoxib treatment were proteins involved in diverse cellular functions including glycolysis, protein biosynthesis, DNA synthesis, mRNA processing, protein folding, phosphorylation, redox regulation, and molecular chaperon activities. Our study presents a comprehensive analysis of large-scale celecoxib-modulated proteomic alterations, at least some of which may be mechanistically related to the COX-2-independent chemopreventive effect of celecoxib. (Cancer Epidemiol Biomarkers Prev 2006;15(9):1598 -606)

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Section: Discussionmentioning

confidence: 99%

Proteomic Profiling Identifies Cyclooxygenase-2-Independent Global Proteomic Changes by Celecoxib in Colorectal Cancer Cells

Lou

Xiao²,

Stauffer³

et al. 2006

Cancer Epidemiology, Biomarkers &Amp; Prevention

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“…One of the substrates for B1 kinase has been demonstrated in vitro to be the viral single-stranded DNA binding protein (2). It will be interesting to determine whether BGLF4 also plays a role in modifying cellular transcriptional or DNA replication machinery during EBV infection.…”

Section: Discussionmentioning

confidence: 99%

A Protein Kinase Activity Associated with Epstein-Barr Virus BGLF4 Phosphorylates the Viral Early Antigen EA-D In Vitro

Chen

Chang

Huang

et al. 2000

J Virol

105

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The Epstein-Barr virus (EBV) open reading frame BGLF4 was identified as a potential Ser/Thr protein kinase gene through the recognition of amino acid sequence motifs characteristic of conserved regions within the catalytic domains of protein kinases. In order to investigate this potential kinase activity, BGLF4 was expressed in Escherichia coli and the purified protein was used to generate a specific antiserum. Recombinant vaccinia virus vTF7-3, which expresses the T7 RNA polymerase, was used to infect 293 and 293T cells after transient transfection with a plasmid containing BGLF4 under the control of the T7 promoter. Autophosphorylation of the BGLF4 protein was demonstrated using the specific antiserum in an immune complex kinase assay. In addition, EBNA-1-tagged BGLF4 and EBNA-1 monoclonal antibody 5C11 were used to demonstrate the specificity of the kinase activity and to locate BGLF4 in the cytoplasm of transfected cells. Manganese ions were found to be essential for autophosphorylation of BGLF4, and magnesium can stimulate the activity. BGLF4 can utilize GTP, in addition to ATP, as a phosphate donor in this assay. BGLF4 can phosphorylate histone and casein in vitro. Among the potential viral protein substrates we examined, the EBV early antigen (EA-D, BMRF1), a DNA polymerase accessory factor and an important transactivator during lytic infection, was found to be phosphorylated by BGLF4 in vitro. Amino acids 1 to 26 of BGLF4, but not the predicted conserved catalytic domain, were found to be essential for autophosphorylation of BGLF4.Protein kinases are known to be involved in the regulation of a wide variety of eukaryotic cellular functions including cell metabolism, cell cycle control, hormone response, and control of transcription and translation. Studying viral protein kinases might therefore lead to an understanding of the mechanisms of virus replication and virus-cell interactions. Most of the protein kinases of the retroviruses are Tyr protein kinases, such as v-src and v-erb, which may contribute to the growth transformation phenotype of the virally infected host cells (for a review, see reference 32). The first protein kinase gene demonstrated in a eukaryotic DNA virus was that contained in the unique short (US) regions of the related human and porcine alphaherpesviruses, herpes simplex virus type 1 (HSV-1), and pseudorabies virus (20). Other protein kinases have been reported in DNA viruses, including protein kinase B1 of the poxviruses (45, 46) and ORF9 of baculovirus (42).Phosphorylation of cellular and viral proteins, which has been observed during lytic infection of cells by herpesviruses, seems to be a common phenomenon which involves a number of different protein kinase activities (21). Two groups of viral protein kinase activities, US3 and UL13, have been identified in alphaherpesviruses. The US3 gene of HSV-1 (37) and the VZV66 gene of varicella-zoster virus (VZV) (19) were predicted to encode protein kinases on the basis of their strong similarity to the family of eukaryotic serine/threon...

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“…Temperature shift experiments indicate that the B1 kinase is required throughout DNA replication, although its specific role in unknown. The S2 and Sa subunits of the 40S ribosome are cellular substrates of B1, while the only known viral substrate of the kinase is the vaccinia virus H5 protein (1,4,5). The H5 gene encodes a 22.3-kDa protein that is synthesized during both the early and late phases of viral gene expression (39).…”

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confidence: 99%

Clustered Charge-to-Alanine Mutagenesis of the Vaccinia Virus H5 Gene: Isolation of a Dominant, Temperature-Sensitive Mutant with a Profound Defect in Morphogenesis

DeMasi

Traktman

2000

J Virol

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The vaccinia virus H5 gene encodes a 22.3-kDa phosphoprotein that is expressed during both the early and late phases of viral gene expression. It is a major component of virosomes and has been implicated in viral transcription and, as a substrate of the B1 kinase, may participate in genome replication. To enable a genetic analysis of the role of H5 during the viral life cycle, we used clustered charge-to-alanine mutagenesis in an attempt to create a temperature-sensitive (ts) virus with a lesion in the H5 gene. Five mutant viruses were isolated, with one of them, tsH5-4, having a strong ts phenotype as assayed by plaque formation and measurements of 24-h viral yield. Surprisingly, no defects in genome replication or viral gene expression were detected at the nonpermissive temperature. By electron microscopy, we observed a profound defect in the early stages of virion morphogenesis, with arrest occurring prior to the formation of crescent membranes or immature particles. Nonfunctional, "curdled" virosomes were detected in tsH5-4 infections at the nonpermissive temperature. These structures appeared to revert to functional virosomes after a temperature shift to permissive conditions. We suggest an essential role for H5 in normal virosome formation and the initiation of virion morphogenesis. By constructing recombinant genomes containing two H5 alleles, wild type and H5-4, we determined that H5-4 exerted a dominant phenotype. tsH5-4 is the first example of a dominant ts mutant isolated and characterized in vaccinia virus.Vaccinia virus is the prototypical member of the Poxvirus family, members of which include the human pathogens variola virus, the causative agent of smallpox, and molluscum contagiosum virus, which causes benign but long-lived skin lesions. The 192-kb double-stranded DNA genome of vaccinia virus contains approximately 200 genes, enabling the virus to replicate quite autonomously within the cytoplasm of infected cells (17,31). The virus encodes a complex transcriptional machinery which directs the expression of three classes of temporally regulated genes: early, which encode the proteins required for replication of the viral genome, and intermediate and late, among whose products are those required for virion morphogenesis. Virion formation commences from cytoplasmic sites known as virosomes or viral factories, which contain viral DNA and viral proteins. Membrane crescents form, begin to enclose the virosome contents, and then enlarge and seal to form the visually distinguishable immature (IV) and mature (IMV) forms of the intracellular class of virions. A subset of these virions become wrapped in membranes derived from the transGolgi network and exit the cell. The genome also encodes a large number of effector proteins that enable the virus to evade host defenses.Protein phosphorylation is known to play a crucial role in the regulation of many cellular processes such as initiation of DNA replication, signal transduction, and cell cycle control. Similarly, vaccinia virus regulates its life cycle by ...

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Ribosomal protein S2/Sa kinase purified from HeLa cells infected with vaccinia virus corresponds to the B1R protein kinase and phosphorylates in vitro the viral ssDNA-binding protein

Cited by 26 publications

References 28 publications

Proteomic Profiling Identifies Cyclooxygenase-2-Independent Global Proteomic Changes by Celecoxib in Colorectal Cancer Cells

Proteomic Profiling Identifies Cyclooxygenase-2-Independent Global Proteomic Changes by Celecoxib in Colorectal Cancer Cells

A Protein Kinase Activity Associated with Epstein-Barr Virus BGLF4 Phosphorylates the Viral Early Antigen EA-D In Vitro

Clustered Charge-to-Alanine Mutagenesis of the Vaccinia Virus H5 Gene: Isolation of a Dominant, Temperature-Sensitive Mutant with a Profound Defect in Morphogenesis

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