Linked Life Data

10801894

Source:http://linkedlifedata.com/resource/pubmed/id/10801894

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
29
pubmed:dateCreated
2000-8-24
pubmed:abstractText
Activation of ERK-1 and -2 by H(2)O(2) in a variety of cell types requires epidermal growth factor receptor (EGFR) phosphorylation. In this study, we investigated the activation of ERK by ONOO(-) in cultured rat lung myofibroblasts. Western blot analysis using anti-phospho-ERK antibodies along with an ERK kinase assay using the phosphorylated heat- and acid-stable protein (PHAS-1) substrate demonstrated that ERK activation peaked within 15 min after ONOO(-) treatment and was maximally activated with 100 micrometer ONOO(-). Activation of ERK by ONOO(-) and H(2)O(2) was blocked by the antioxidant N-acetyl-l-cysteine. Catalase blocked ERK activation by H(2)O(2), but not by ONOO(-), demonstrating that the effect of ONOO(-) was not due to the generation of H(2)O(2). Both H(2)O(2) and ONOO(-) induced phosphorylation of EGFR in Western blot experiments using an anti-phospho-EGFR antibody. However, the EGFR tyrosine kinase inhibitor AG1478 abolished ERK activation by H(2)O(2), but not by ONOO(-). Both H(2)O(2) and ONOO(-) activated Raf-1. However, the Raf inhibitor forskolin blocked ERK activation by H(2)O(2), but not by ONOO(-). The MEK inhibitor PD98059 inhibited ERK activation by both H(2)O(2) and ONOO(-). Moreover, ONOO(-) or H(2)O(2) caused a cytotoxic response of myofibroblasts that was prevented by preincubation with PD98059. In a cell-free kinase assay, ONOO(-) (but not H(2)O(2)) induced autophosphorylation and nitration of a glutathione S-transferase-MEK-1 fusion protein. Collectively, these data indicate that ONOO(-) activates EGFR and Raf-1, but these signaling intermediates are not required for ONOO(-)-induced ERK activation. However, MEK-1 activation is required for ONOO(-)-induced ERK activation in myofibroblasts. In contrast, H(2)O(2)-induced ERK activation is dependent on EGFR activation, which then leads to downstream Raf-1 and MEK-1 activation.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
21
pubmed:volume
275
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
22479-86
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Peroxynitrite targets the epidermal growth factor receptor, Raf-1, and MEK independently to activate MAPK.
pubmed:affiliation
Laboratory of Pulmonary Pathobiology, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.