Erythropoietin-Stimulated Raf-1 Tyrosine Phosphorylation is Associated with the Tyrosine Kinase Lyn in J2E Erythroleukemic Cells

Peta Tilbrook, S.M. Colley, D.J. Mccarthy, R. Marais, Peter Klinken

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

The serine/threonine kinase Raf-1 is crucial for transducing intracellular signals emanating from numerous growth factors. Here we used the J2E erythroid cell line transformed by the v-raf/v-myc oncogenes to examine the effects of erythropoietin on endogenous Raf-1 activity. Despite the presence of constitutively active v-raf in these cells, Raf-1 exokinase activity increased after erythropoietin stimulation. This increase in enzymatic activity coincided with tyrosine phosphorylation of Raf-1 on residue Y341. Significantly, the tyrosine kinase Lyn coimmunoprecipitated with Raf-1, and Raf-1 was not tyrosine-phosphorylated in a J2E subclone lacking Lyn. Therefore, it was concluded that Lyn may be the kinase responsible for tyrosine phosphorylating Raf-1 and increasing its exokinase activity in response to erythropoietin. (C) 2001 Elsevier Science.
Original languageEnglish
Pages (from-to)128-132
JournalArchives of Biochemistry and Biophysics
Volume396
Issue number1
DOIs
Publication statusPublished - 2001

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