Activation of Mitogen-activated Protein Kinase by H
O
ROLE IN CELL SURVIVAL FOLLOWING OXIDANT INJURY (*)
- From the Section on Gene Expression and Aging, Gerontology Research Center, NIA, National Institutes of Health, Baltimore, Maryland 21224
- § To whom correspondence should be addressed: Gerontology Research Center, Gene Expression and Aging Section, 4940 Eastern Ave., Baltimore, MD 21224. Tel.: 410-558-8197; Fax: 410-558-8335.
Abstract
The mitogen-activated protein kinase (MAPK) family is comprised of key regulatory proteins that control the cellular response
to both proliferation and stress signals. In this study we investigated the factors controlling MAPK activation by H
O
and explored the impact of altering the pathways to kinase activation on cell survival following H
O
exposure. Potent activation (10-20-fold) of extracellular signal-regulated protein kinase (ERK2) occurred within 10 min of
H
O
treatment, whereupon rapid inactivation ensued. H
O
activated ERK2 in several cell types and also moderately activated (3-5-fold) both c-Jun N-terminal kinase and p38/RK/CSBP.
Additionally, H
O
increased the mRNA expression of MAPK-dependent genes c-jun, c-fos, and MAPK phosphatase-1. Suramin pretreatment completely inhibited H
O
stimulation of ERK2, highlighting a role for growth factor receptors in this activation. Further, ERK2 activation by H
O
was blocked by pretreatment with either N-acetyl-cysteine, o-phenanthroline, or mannitol, indicating that metal-catalyzed free radical formation mediates the initiation of signal transduction
by H
O
. H
O
-stimulated activation of ERK2 was abolished in PC12 cells by inducible or constitutive expression of the dominant negative
Ras-N-17 allele. Interestingly, PC12/Ras-N-17 cells were more sensitive than wild-type PC12 cells to H
O
toxicity. Moreover, NIH 3T3 cells expressing constitutively active MAPK kinase (MEK, the immediate upstream regulator of
ERK) were more resistant to H
O
toxicity, while those expressing kinase-defective MEK were more sensitive, than cells expressing wild-type MEK. Taken together,
these studies provide insight into mechanisms of MAPK regulation by H
O
and suggest that ERK plays a critical role in cell survival following oxidant injury.
Footnotes
-
↵* The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
-
↵1 The abbreviations used are:
- ERK
-
extracellular signal-regulated kinase
- JNK1/SAPK
-
c-Jun N-terminal kinase-1
- MAPK
-
mitogen-activated protein kinase
- MBP
-
myelin basic protein
- MEK
-
MAP kinase kinase
- MEK
-
wild-type MEK
- MEK
-
constitutively active MEK
- MEK
-
kinase-defective MEK
- MKP-1
-
MAPK phosphatase-1
- rMKP-1
-
rat MKP-1
- SMC
-
aortic smooth muscle cell primary cultures
- MOPS
-
4-morpholinepropanesulfonic acid
- p38/RK/CSBP
-
38-kDa MAPK-related protein/reactivating kinase/cytokine-suppressive anti-inflammatory drug binding protein
- UVC
-
short wavelength UV radiation.
-
- Received November 6, 1995.
- Revision received December 13, 1995.
- © 1996 by The American Society for Biochemistry and Molecular Biology, Inc.
