Linked Life Data

12429742

Source:http://linkedlifedata.com/resource/pubmed/id/12429742

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2003-1-13
pubmed:abstractText
Overexpression of the epidermal growth factor receptor (EGFR) and its association with the tyrosine kinase, c-Src, is correlated with increased cellular proliferation and tumorigenesis. Previous studies have shown that EGFR and c-Src co-overexpression and association leads to the c-Src-mediated phosphorylation of tyrosine 845 of the EGFR and that mutation of Tyr(845) ablates epidermal growth factor (EGF)-induced DNA synthesis. Here, we investigate the contribution of the signal transducers and activators of transcription (STAT5b) in the signaling pathways regulated by EGFR and c-Src overexpression in human breast tumor cell lines as well as in a mouse fibroblast model (C3H10T1/2). We demonstrate that 1) activation of STAT5b by EGF requires overexpression of the EGFR, 2) co-overexpression of c-Src alone does not result in EGF-induced activation of STAT5b but enhances that seen in EGFR-overexpressing cells, and 3) EGF-induced tyrosine phosphorylation of STAT5b requires Tyr(845) of the EGFR. Furthermore, the stable overexpression of a kinase-defective c-Src in the context of EGFR overexpression results in a decrease in the tyrosine phosphorylation of STAT5b in response to EGF and a more dramatic decrease in EGF-induced transcriptional activation of STAT5b, suggesting an integral role for c-Src in the physiological actions of STAT5b. Using a dominant negative STAT5b, we provide evidence that one such physiological action is to mediate EGF-induced DNA-synthesis. Finally, the use of site-specific tyrosine mutants demonstrates that EGF-induced phosphorylation of STAT5b involves not only tyrosine 699 of STAT5b, which is required for its transcriptional activation, but also three previously identified tyrosines in the C terminus of STAT5b (Tyr(725)/Tyr(740)/Tyr(743)).
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
17
pubmed:volume
278
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1671-9
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
STAT5b, a Mediator of Synergism between c-Src and the Epidermal Growth Factor Receptor.
pubmed:affiliation
Departments of Internal Medicine and Microbiology and the Cancer Center, University of Virginia Health System, Charlottesville, Virginia 22908.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.