Regulation of the mitogen-activated protein kinase p44 ERK activity during anoxia/recovery in rainbow trout hypodermal fibroblasts.

Carlo G Ossum, Tune Wulff, Else K Hoffmann

Institute of Molecular Biology and Physiology, Department of Biochemistry, The August Krogh Building, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark. cgossum@aki.ku.dk

The Journal of experimental biology 2006 May

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It is well known from various mammalian cells that anoxia has a major impact on the mitogen-activated protein kinase ERK, but a possible similar effect in fish cells has not been investigated. Here we characterise a p44ERK-like protein in the rainbow trout cell line RTHDF and study the effect of (i) serum stimulation, (ii) sodium azide (chemical anoxia) and removal of azide (recovery) and (iii) anoxia (P(O)2<0.1%) and recovery. During both chemical and true anoxia p44ERK was inhibited and recovery resulted in robust reactivation of p44ERK activity, far above the initial level. The inhibition was secondary to activation of p38(MAPK) and the increase was MEK dependent, as SB203580 inhibited the dephosphorylation during anoxia and the presence of PD98059 inhibited phosphorylation of p44ERK during recovery. In addition, we demonstrated that the reactivation of p44ERK during recovery also was dependent on reactive oxygen species and a PP1/PP2A-like phosphatase.

Citation

Carlo G Ossum, Tune Wulff, Else K Hoffmann. Regulation of the mitogen-activated protein kinase p44 ERK activity during anoxia/recovery in rainbow trout hypodermal fibroblasts. The Journal of experimental biology. 2006 May;209(Pt 9):1765-76