RRC ID 67980
Author Matsuguchi T, Musikacharoen T, Johnson TR, Kraft AS, Yoshikai Y.
Title A novel mitogen-activated protein kinase phosphatase is an important negative regulator of lipopolysaccharide-mediated c-Jun N-terminal kinase activation in mouse macrophage cell lines.
Journal Mol Cell Biol
Abstract We have isolated a cDNA homologous to known dual-specificity phosphatases from a mouse macrophage cDNA library and termed it MKP-M (for mitogen-activated protein kinase phosphatase isolated from macrophages). Three other presumed splice variant isoforms have also been identified for MKP-M. The longest and most abundant mRNA contains an open reading frame corresponding to 677 amino acids and produces an 80-kDa protein. The deduced amino acid sequence of MKP-M is most similar to those of hVH-5 (or mouse M3/6) and VHP1, a Caenorhabditis elegans tyrosine phosphatase. It includes an N-terminal rhodanase homology domain, the extended active-site sequence motif (V/L)X(V/I)HCXAG(I/V)SRSXT(I/V)XXAY(L/I)M (where X is any amino acid), and a C-terminal PEST sequence. Northern blot analysis revealed a dominant MKP-M mRNA species of approximately 5.5 kb detected ubiquitously among all tissues examined. MKP-M was constitutively expressed in mouse macrophage cell lines, and its expression levels were rapidly increased by lipopolysaccharide (LPS) stimulation but not by tumor necrosis factor alpha (TNF-alpha), gamma interferon, interleukin-2 (IL-2), or IL-15 stimulation. Immunocytochemical analysis showed MKP-M to be present within cytosol. When expressed in COS7 cells, MKP-M blocks activation of mitogen-activated protein kinases with the selectivity c-Jun N-terminal kinase (JNK) >> p38 = extracellular signal-regulated kinase. Furthermore, expression of a catalytically inactive form of MKP-M in a mouse macrophage cell line increased the intensity and duration of JNK activation and TNF-alpha secretion after LPS stimulation, suggesting that MKP-M is at least partially responsible for the desensitization of LPS-mediated JNK activation and cytokine secretion in macrophages.
Volume 21(20)
Pages 6999-7009
Published 2001-10-1
DOI 10.1128/MCB.21.20.6999-7009.2001
PMID 11564882
PMC PMC99875
MeSH Amino Acid Sequence Animals Blotting, Northern COS Cells Catalysis Cell Line DNA, Complementary / metabolism Down-Regulation Dual-Specificity Phosphatases Enzyme Activation Enzyme-Linked Immunosorbent Assay Escherichia coli / metabolism Gene Expression Regulation, Enzymologic Gene Library Genes, Dominant Humans Immunoblotting Immunohistochemistry Interferon-gamma / pharmacology Interleukin-15 / pharmacology Interleukin-2 / pharmacology JNK Mitogen-Activated Protein Kinases Lipopolysaccharides / metabolism* MAP Kinase Signaling System* Macrophages / enzymology* Mice Mitogen-Activated Protein Kinase Phosphatases Mitogen-Activated Protein Kinases / metabolism* Models, Genetic Molecular Sequence Data Phosphoric Monoester Hydrolases / chemistry* Phosphoric Monoester Hydrolases / metabolism Plasmids / metabolism Precipitin Tests Protein Tyrosine Phosphatases / biosynthesis* Protein Tyrosine Phosphatases / genetics Protein Tyrosine Phosphatases / metabolism* RNA, Messenger / metabolism Recombinant Proteins / metabolism Time Factors Tissue Distribution Transfection Tumor Necrosis Factor-alpha / pharmacology Tyrosine / metabolism p38 Mitogen-Activated Protein Kinases
IF 3.611
Human and Animal Cells RAW 264(RCB0535) COS-7(RCB0539)