title: MKP-1 contributes to oxidative stress-induced apoptosis via inactivation of ERK1/2 in SH-SY5Y cells.
abstract: Mitogen-activated protein (MAP) kinase phosphatase-1 (MKP-1) is a dual specificity phosphatase that negatively regulates the MAP kinases. In this study, we found that levels of MKP-1 expression were transiently decreased within 3h, followed by an increase 6-9h after H2O2-induced oxidative stress in human neuroblastoma SH-SY5Y cells. There was a strong negative correlation between MKP-1 expression and ERK1/2 phosphorylation levels. Treatment of cells with a proteasomal inhibitor MG132 decreased the oxidative stress-induced degradation of MKP-1, resulting in dephosphorylation of ERK1/2. MG132 potentiated hydrogen peroxide-induced cell death, which was attenuated by a phosphatase inhibitor sodium orthovanadate. Suppression of MKP-1 expression by transfection with siRNA duplexes specific to MKP-1 transcript resulted in a decrease in oxidative stress-induced cell death. These data therefore suggest that MKP-1, a negative regulator of ERK1/2, plays a proapoptotic role in oxidative stress-induced cell death in a neuronal cell line.
authors.affiliation: Department of Manufacturing Pharmacy, College of Pharmacy, Seoul National University, Seoul 110-460, Republic of Korea.
authors.forename: Gab Seok
authors.initials: GS
authors.lastname: Kim
authors.forename: Yoo Keum
authors.initials: YK
authors.lastname: Choi
authors.forename: Sun Sook
authors.initials: SS
authors.lastname: Song
authors.forename: Won-Ki
authors.initials: WK
authors.lastname: Kim
authors.forename: Byung Hee
authors.initials: BH
authors.lastname: Han
mesh_terms: D017209:Apoptosis / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D054638:Dual Specificity Phosphatase 1; D004790:Enzyme Induction; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D017874:Immediate-Early Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D009447:Neuroblastoma / Q000201:enzymology; D018384:Oxidative Stress / Q000502:physiology*; D010749:Phosphoprotein Phosphatases / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D054645:Protein Phosphatase 1; D017027:Protein Tyrosine Phosphatases / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D034741:RNA, Small Interfering / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D025801:Ubiquitin / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D017874:Immediate-Early Proteins; D034741:RNA, Small Interfering; D025801:Ubiquitin; D006861:Hydrogen Peroxide; D048049:Extracellular Signal-Regulated MAP Kinases; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; C517019:DUSP1 protein, human; D054638:Dual Specificity Phosphatase 1; D017027:Protein Tyrosine Phosphatases; D046988:Proteasome Endopeptidase Complex