title: Activation of Src-like p56/p53lyn tyrosine kinase by ionizing radiation.
abstract: Mammalian cells respond to ionizing radiation (IR) with cell cycle arrest, activation of DNA repair, and induction of early response genes. The present work has examined the involvement of Src-like protein-tyrosine kinases in the response of irradiated HL-60 myeloid leukemia cells. The results demonstrate little if any effect of IR on p59fyn, p56lck, and pp60c-src activity. In contrast, HL-60 cells responded to x-ray exposure with activation of p56/p53lyn. At a dose of 200 centigrays, induction of p56/p53lyn activity was detectable at 15 min. Doses as low as 50 centigrays were effective in activating p56/p53lyn. H2O2 and the scavenger N-acetylcysteine had no detectable effect on p56/p53lyn activation, while the protein-tyrosine kinase inhibitors, herbimycin and genistein, blocked induction by IR. The results also demonstrate that incubation of a glutathione S-transferase-Lyn fusion protein with lysates of irradiated HL-60 cells is associated with binding of the cell cycle regulatory protein, p34cdc2. The interaction of p56/p53lyn and p34cdc was confirmed in similar experiments with a glutathione S-transferase-Cdc2 fusion protein. Moreover, coimmunoprecipitation studies demonstrate the selective binding of activated p56/p53lyn to p34cdc2 in irradiated cells. These findings indicate that IR activates p56/p53lyn in HL-60 cells and that this tyrosine kinase may contribute to the regulation of p34cdc2.
authors.affiliation: Division of Cancer Pharmacology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: S
authors.initials: S
authors.lastname: Kharbanda
authors.forename: Z M
authors.initials: ZM
authors.lastname: Yuan
authors.forename: E
authors.initials: E
authors.lastname: Rubin
authors.forename: R
authors.initials: R
authors.lastname: Weichselbaum
authors.forename: D
authors.initials: D
authors.lastname: Kufe
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004789:Enzyme Activation / Q000528:radiation effects*; D016166:Free Radical Scavengers; D006801:Humans; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D017382:Reactive Oxygen Species; D014407:Tumor Cells, Cultured; D014965:X-Rays; D019061:src-Family Kinases
chemical_list: D016166:Free Radical Scavengers; D009838:Oligodeoxyribonucleotides; D017382:Reactive Oxygen Species; D011505:Protein-Tyrosine Kinases; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); C060902:lyn protein-tyrosine kinase; D019061:src-Family Kinases