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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
7
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pubmed:dateCreated |
2001-3-12
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pubmed:abstractText |
The K8 locus in Kaposi's sarcoma-associated herpesvirus (KSHV) is syntenic with the Epstein-Barr virus (EBV) BZLF (Z) locus and expresses three alternatively spliced transcripts. The fully spliced transcript encodes K-bZIP, the KSHV homologue of the EBV immediate-early transcriptional transactivator Z. Here we show that despite the presence of alternatively spliced transcripts, the protein from the fully spliced RNA, K-bZIP, is the principal product detectable in KSHV-infected B cells. The protein is detected only in lytically infected cells and is localized to the nucleus. We further characterized K-bZIP by determining its phosphorylation status. Phosphoamino acid analysis revealed phosphorylation on serine and threonine. Analysis of the sites of K-bZIP phosphorylation by tandem mass spectrometry revealed that K-bZIP was phosphorylated on Thr 111 and Ser 167. These phosphorylation sites are contained within cyclin-dependent kinase (CDK) recognition sites with the consensus sequence (S/T)PXR, suggesting that K-bZIP could be phosphorylated by CDKs. We tested this hypothesis using an in vitro kinase reaction performed in whole-cell extracts that resemble in vivo conditions more closely than standard in vitro kinase reactions. We found that the three CDK-cyclin complexes we tested phosphorylated K-bZIP but not the control ORF 73 protein, which contains four (S/T)PXR sites. Ectopic expression of K-bZIP cannot reactivate KSHV from latency, and single and double mutants of K-bZIP in which alanines replaced the phosphorylated serine and/or threonine also failed to induce lytic replication. These studies indicate that K-bZIP is a substrate for CDKs and should inform further functional analyses of the protein.
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pubmed:grant |
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-10091993,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-10194235,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-10202152,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-10233912,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-10424174,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-10428798,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-10498178,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-10516009,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-10516043,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-10544116,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-10753712,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-1719341,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-1821323,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-1967430,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-2987963,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-6246487,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-7632932,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-7670109,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-7700311,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-7997879,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-8612236,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-8654372,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-8705864,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-8779443,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-8839859,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-8962146,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-9002520,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-9060666,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-9108016,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-9323208,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-9422503,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-9680119,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-9709807,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-9710583,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-9724796,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-9733836,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-9765394,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-9878608,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11238844-9971770
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Apr
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pubmed:issn |
0022-538X
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:volume |
75
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
3175-84
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pubmed:dateRevised |
2009-11-19
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pubmed:meshHeading |
pubmed-meshheading:11238844-Amino Acid Sequence,
pubmed-meshheading:11238844-Animals,
pubmed-meshheading:11238844-Basic-Leucine Zipper Transcription Factors,
pubmed-meshheading:11238844-COS Cells,
pubmed-meshheading:11238844-Cyclin-Dependent Kinases,
pubmed-meshheading:11238844-DNA-Binding Proteins,
pubmed-meshheading:11238844-G-Box Binding Factors,
pubmed-meshheading:11238844-Herpesvirus 8, Human,
pubmed-meshheading:11238844-Molecular Sequence Data,
pubmed-meshheading:11238844-Phosphorylation,
pubmed-meshheading:11238844-Protein Isoforms,
pubmed-meshheading:11238844-Rabbits,
pubmed-meshheading:11238844-Serine,
pubmed-meshheading:11238844-Threonine,
pubmed-meshheading:11238844-Transcription Factors,
pubmed-meshheading:11238844-Viral Proteins,
pubmed-meshheading:11238844-Virus Activation,
pubmed-meshheading:11238844-Virus Latency
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pubmed:year |
2001
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pubmed:articleTitle |
Kaposi's sarcoma-associated herpesvirus K-bZIP protein is phosphorylated by cyclin-dependent kinases.
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pubmed:affiliation |
Departments of Microbiology and Immunology, University of California San Francisco, San Francisco, California 94143, USA.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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