Open AccessActivation of the pp90rsk and mitogen-activated serine/threonine protein kinases by ionizing radiation.
Author(s) -
Surender Kharbanda,
Ahamed Saleem,
Timothy D. Shafman,
Yutaka Emoto,
Ralph R. Weichselbaum,
Donald Küfe
Publication year - 1994
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.91.12.5416
Subject(s) - protein kinase a , mitogen activated protein kinase kinase , kinase , map kinase kinase kinase , ask1 , mitogen activated protein kinase , map2k7 , biology , microbiology and biotechnology , ribosomal s6 kinase , c raf , cyclin dependent kinase 2 , mapk14 , protein kinase r , phosphorylation , chemistry , p70 s6 kinase 1 , protein kinase b
The cellular response to ionizing radiation (IR) includes induction of the c-jun and EGR1 early response genes. The present work has examined potential cytoplasmic signaling cascades that transduce IR-induced signals to the nucleus. The results demonstrate activation of the 40S ribosomal protein S6 kinase, pp90rsk, in human U-937 myeloid leukemia cells. Partial purification of pp90rsk by affinity chromatography demonstrated an increase in S6 peptide phosphorylation when comparing irradiated with control cells. IR-induced activation of pp90rsk was further confirmed in immune-complex kinase assays. In contrast to these findings, there was no detectable induction of pp70S6K. Previous work has demonstrated that mitogen-activated protein kinase activates pp90rsk. The present results further show that IR treatment is associated with induction of mitogen-activated protein kinase activity and that this event is temporally related to activation of pp90rsk and early response gene expression. These findings suggest that activation of the mitogen-activated protein kinase/pp90rsk cascade is involved in the response of cells to IR exposure.