Linked Life Data

16431927

Source:http://linkedlifedata.com/resource/pubmed/id/16431927

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
14
pubmed:dateCreated
2006-4-3
pubmed:abstractText
Tyrosine phosphorylation of the transcription factors Stat1 and Stat3 is required for them to dimerize, translocate to the nucleus, and induce gene transcription. Nuclear Stat1 and Stat3 are dephosphorylated and deactivated by the T-cell protein-tyrosine phosphatase (TC-PTP), which facilitates the return of both proteins to the cytoplasm. The protein kinase PKR plays an important role in translational control through the modulation of eukaryotic initiation factor-2alpha phosphorylation. Previous data have implicated PKR in cell signaling via regulation of Stat1 and Stat3, but the molecular mechanisms underlying these events have remained elusive. Using PKR(-/-) mouse embryonic fibroblasts and a conditionally active form of human PKR, we demonstrate herein that tyrosine (but not serine) phosphorylation of either Stat1 or Stat3 is impaired in cells with activated kinase. This reduction in Stat1 and Stat3 tyrosine phosphorylation by active PKR proceeds through TC-PTP, which is a substrate of the eukaryotic initiation factor-2alpha kinase both in vitro and in vivo. TC-PTP phosphorylation alone is insufficient to increase its in vivo phosphatase activity unless accompanied by the inhibition of protein synthesis as a result of PKR activation. These data reveal a novel function of PKR as a negative regulator of Stat1 and Stat3 with important implications in cell signaling.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
7
pubmed:volume
281
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
9439-49
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
The catalytic activity of the eukaryotic initiation factor-2alpha kinase PKR is required to negatively regulate Stat1 and Stat3 via activation of the T-cell protein-tyrosine phosphatase.
pubmed:affiliation
Department of Oncology, Sir Mortimer B. Davis Jewish General Hospital, Montreal, Québec, Canada.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't