EGF receptor phosphorylation is affected by ionizing radiation

Tzipora Goldkorn, Naomi Balaban, Mary Shannon, Karen Matsukuma

Research output: Contribution to journalArticle

77 Scopus citations

Abstract

Eukaryotic cells respond to ionizing radiation with cell cycle arrest, activation of DNA repair mechanisms, and lethality. However, little is known about the molecular mechanisms that constitute these responses. Here we report that ionizing radiation enhances epidermal growth factor (EGF) receptor tyrosine phosphorylation in intact cells as well as in isolated membranes of A431 cells, Phosphoamino acid analysis revealed that ionizing radiation preferentially enhances tyrosine phosphorylation, while EGF enhances the phosphorylation of all three phosphoamino acids (serine, threonine and tyrosine) of the EGF receptor. In addition, radiation reduces the turnover rate of the EGF receptor, while EGF increases the rate of the receptor turnover and down-regulation. Moreover, the confined radiation-induced phosphorylation of tyrosine residues is inhibited by genistein, indicating that this phosphorylation of EGF receptor is due to protein tyrosine kinase activation. These studies provide novel insights into the capacity of radiation to modulate EGF receptor phosphorylation and function. The radiation-induced elevation in the EGF receptor tyrosine phosphorylation and the receptor's slower rate of turnover are discussed in terms of their possible role in cell growth and apoptosis modulation.

Original languageEnglish (US)
Pages (from-to)289-299
Number of pages11
JournalBiochimica et Biophysica Acta - Molecular Cell Research
Volume1358
Issue number3
DOIs
StatePublished - Oct 11 1997

Keywords

  • Epidermal growth factor receptor
  • Ionizing radiation
  • Tyrosine phosphorylation

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology
  • Biophysics

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