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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2000-2-10
pubmed:abstractText
Replication of the human immunodeficiency virus type 1 (HIV-1) is inhibited by interferons (IFNs), in part through activity of the IFN-inducible protein kinase PKR. To escape this antiviral effect, HIV-1 has developed strategies for blocking PKR function. We have previously shown that the HIV-1 Tat protein can associate with PKR in vitro and in vivo and inhibit PKR activity. Here we present evidence that Tat can inhibit PKR activity by both RNA-dependent and RNA-independent mechanisms. Tat inhibited PKR activation by the non-RNA activator heparin, and also suppressed PKR basal level autophosphorylation in the absence of RNA. However, when Tat and dsRNA were preincubated, the amount of Tat required to inhibit PKR activation by dsRNA depended on the dsRNA concentration. In addition to its function in vitro, Tat can also reverse translation inhibition mediated by PKR in COS cells. The Tat amino acid sequence required for interaction with PKR was mapped to residues 40-58, overlapping the hydrophobic core and basic region of HIV-1 Tat. Alignment of amino acid sequences of Tat and eIF-2alpha indicates similarity between the Tat-PKR binding region and the residues around the eIF-2alpha phosphorylation site, suggesting that Tat and eIF-2alpha may bind to the same site on PKR.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0003-9861
pubmed:author
pubmed:copyrightInfo
Copyright 2000 Academic Press.
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
373
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
361-7
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:10620360-Amino Acid Sequence, pubmed-meshheading:10620360-Animals, pubmed-meshheading:10620360-COS Cells, pubmed-meshheading:10620360-Enzyme Activation, pubmed-meshheading:10620360-Eukaryotic Initiation Factor-2, pubmed-meshheading:10620360-Gene Products, tat, pubmed-meshheading:10620360-HIV-1, pubmed-meshheading:10620360-Heparin, pubmed-meshheading:10620360-Humans, pubmed-meshheading:10620360-Molecular Sequence Data, pubmed-meshheading:10620360-Phosphorylation, pubmed-meshheading:10620360-Protein Binding, pubmed-meshheading:10620360-RNA, Double-Stranded, pubmed-meshheading:10620360-Recombinant Fusion Proteins, pubmed-meshheading:10620360-Sequence Alignment, pubmed-meshheading:10620360-Viral Proteins, pubmed-meshheading:10620360-eIF-2 Kinase, pubmed-meshheading:10620360-tat Gene Products, Human Immunodeficiency Virus
pubmed:year
2000
pubmed:articleTitle
HIV-I TAT inhibits PKR activity by both RNA-dependent and RNA-independent mechanisms.
pubmed:affiliation
Lerner Research Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, Ohio 44195, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't