Activation of the pp90[sup rsk] and mitogen-activated serine/threonine protein kinases by ionizing radiation
- Harvard Medical School, Boston, MA (United States)
- Univ. of Chicago, IL (United States)
The cellular response to ionizing radiation (IR) includes induction of the c-jun and EGRI 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, pp90[sup rsk], in human U-937 myeloid leukemia cells. Partial purification of pp90[sup rsk] by affinity chromatography demonstrated an increase in S6 peptide phosphorylation when comparing irradiated with control cells. IR-induced activation of pp90[sup rsk] was further confirmed in immune-complex kinase assays. In contrast to these findings, there was no detectable induction of pp70[sup rsk]. Previous work has demonstrated that mitogen-activated protein kinase activates pp90[sup rsk]. 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 pp90[sup rsk] and early response gene expression. These findings suggest that activation of the mitogen-activated protein kinase/pp90[sup rsk] cascade is involved in the response of cells to IR exposure.
- OSTI ID:
- 6851247
- Journal Information:
- Proceedings of the National Academy of Sciences of the United States of America; (United States), Vol. 91:12; ISSN 0027-8424
- Country of Publication:
- United States
- Language:
- English
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PHOSPHOTRANSFERASES
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