Peroxynitrite activates mitogen‐activated protein kinase (MAPK) via a MEK‐independent pathway: a role for protein kinase C

FEBS Letters

Post, J.A¹  Verkleij, A¹  Bapat, S¹ 

[1] Institute of Biomembranes, Department of Molecular Cell Biology, Universiteit Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands

关键词: Peroxynitrite;    Mitogen-activated protein kinase;    Protein kinase C;    Mitogen-activated protein kinase kinase;    Oxidative stress;    Signal transduction;    MAPK;    mitogen-activated protein kinase;    ERK;    extracellular signal-regulated kinase;    ONOO−;    peroxynitrite;    MEK;    MAPK kinase;    PBSglc;    phosphate-buffered saline;    PKC;    protein kinase C;    PDBU;    phorbol-12;    13-dibutyrate;    EGF;    epidermal growth factor;    EGFR;    EGF receptor;   

DOI  :  10.1016/S0014-5793(01)02511-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

In this study we show that phosphorylation of extracellular signal-regulated kinase (ERK1/2; also known as p44/42MAPK) following peroxynitrite (ONOO⁻) exposure occurs via a MAPK kinase (MEK)-independent but PKC-dependent pathway in rat-1 fibroblasts. ONOO⁻-mediated ERK1/2 phosphorylation was not blocked by MEK inhibitors PD98059 and U0126. Furthermore, no increase in MEK phosphorylation was detected upon ONOO⁻ treatment. Staurosporine was used to investigate whether protein kinase C (PKC) is involved. This was confirmed by down-regulation of PKC by phorbol-12,13-dibutyrate, which resulted in significant reduction of ERK1/2 phosphorylation by ONOO⁻, implying that activation of ERK by ONOO⁻ depends on activation of PKC. Indeed, PKCα and ϵ were activated upon ONOO⁻ exposure. When cells were treated with ONOO⁻ in a calcium-free buffer, no activation of PKCα was detected. Concomitantly, a reduction of ERK1/2 phosphorylation was observed suggesting that calcium was required for translocation of PKCα and ERK phosphorylation by ONOO⁻. Indeed, ONOO⁻ exposure resulted in increased cytosolic calcium, which depended on the presence of extracellular calcium. Finally, data using Gö6976, an inhibitor of calcium-dependent PKC activation, implied that ONOO⁻-mediated ERK1/2 phosphorylation depends on activation of a calcium-dependent PKC.

【 授权许可】

Unknown