Inactivation of p42 MAP kinase by protein phosphatase 2A and a protein tyrosine phosphatase, but not CL100, in various cell lines

摘要: Abstract Background: Mitogen-activated protein (MAP) kinase is central to a signal transduction pathway that triggers cell proliferation or differentiation. Activation of the p42 mapk isoform requires its phosphorylation at two residues, Thr 183 and Tyr 185, this catalysed by MAP (MAPKK). Relatively little known, however, about enzymes dephosphorylate these thereby inactivating pathway. Recently, CL100 phosphatase has been shown inactivate in vitro dephosphorylating 185 similar rates. CL100, product an immediate early gene, synthesized within one hour stimulating cells with growth factors exposure oxidative stress heat shock. Incubation NIH 3T3 fibroblasts cycloheximide prevents both synthesis inactivation after stimulation serum. Results Depleting preventing induction using stopped Swiss following epidermal factor (EGF), but had no effect on rapid response EGF adipose (3T3-L1) chromaffin (PC12) platelet-derived (PDGF) endothelial (PAE) cells. Moreover, maximal mRNA CL100-like activity did not trigger , which was sustained high level PC12 nerve factor, PAE serum, PDGF. Dephosphorylation suppressed vanadate EGF-stimulated cells; dephosphorylation 183, contrast, elicited vanadate-insensitive activity. Protein phosphatase-2A only acting MAPKK be detected extracts. Phosphorylation also inhibited major vanadate-sensitive 185-specific phosphatase, explaining why rate-limiting for EGF. Conclusion The initiated five minutes endothelial, rather 2A tyrosine distinct from CL100. Induction accompanied number situations.