Hydrogen peroxide activates extracellular signal-regulated kinase via protein kinase C, Raf-1, and MEK1.
We have previously demonstrated that hydrogen peroxide (H2O2) treatment of bovine tracheal myocytes increases the activity of extracellular signal-regulated kinases (ERK), serine/threonine kinases of the mitogen-activated protein (MAP) kinase superfamily thought to play a key role in the transduction of mitogenic signals to the cell nucleus. Moreover, H2O2-induced ERK activation was partially reduced by pretreatment with phorbol 12,13-dibutyrate, which depletes protein kinase C (PKC). In this study, we further examined the signaling intermediates responsible for ERK activation by H2O2 in airway smooth muscle, focusing on MAP kinase/ERK kinase (MEK), a dual-function kinase which is required and sufficient for ERK activation in bovine tracheal myocytes; Raf-1, a serine/threonine kinase known to activate MEK; and PKC. Pretreatment of cells with inhibitors of MEK (PD98059), Raf-1 (forskolin), and PKC (chelerythrine) each reduced H2O2-induced ERK activity. In addition, H2O2 treatment significantly increased both MEK1 and Raf-1 activity. No activation of MEK2 was detected. Together these data suggest that H2O2 may stimulate ERK via successive activation of PKC, Raf-1, and MEK1.
Abe
M K
MK
Department of Pediatrics, University of Chicago, Chicago, Illinois 60637, USA.
Kartha
S
S
Karpova
A Y
AY
Li
J
J
Liu
P T
PT
Kuo
W L
WL
Hershenson
M B
MB
D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000187:drug effects* / Q000378:metabolism; D002417:Cattle; D004789:Enzyme Activation / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D017665:Hydroxyl Radical / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; D020929:Mitogen-Activated Protein Kinase Kinases; D020928:Mitogen-Activated Protein Kinases; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects; D016877:Oxidants / Q000494:pharmacology*; D011493:Protein Kinase C / Q000494:pharmacology; D011494:Protein Kinases / Q000494:pharmacology*; D017346:Protein Serine-Threonine Kinases / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000494:pharmacology; D019908:Proto-Oncogene Proteins c-raf / Q000494:pharmacology; D014132:Trachea / Q000166:cytology / Q000187:drug effects
D016877:Oxidants; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide; D011494:Protein Kinases; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D019908:Proto-Oncogene Proteins c-raf; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; D020929:Mitogen-Activated Protein Kinase Kinases