Ras participates in the activation of p38 MAPK by interleukin-1 by associating with IRAK, IRAK2, TRAF6, and TAK-1.
Interleukin-1 (IL-1) activates p38 MAP kinase via the small G protein Ras, and this activity can be down-regulated by another small G protein Rap. Here we have further investigated the role of Ras and Rap in p38 MAPK activation by IL-1. Transient transfection of cells with constitutively active forms of the known IL-1 signaling components MyD88, IRAK, and TRAF-6, or the upstream kinases MKK6 and MKK3, activated p38 MAPK. Dominant negative forms of these were found to inhibit activation of p38 MAPK by IL-1. Dominant negative RasN17 blocked the effect of the active forms of all but MKK3 and MKK6, indicating that Ras lies downstream of TRAF-6 but upstream of MKK3 and MKK6 on the pathway. Furthermore, the activation of p38 MAPK caused by overexpressing active RasVHa could not be inhibited using dominant negative mutants of MyD88, IRAK, or IRAK-2, or TRAF6, but could be inhibited by dominant negative MKK3 or MKK6. In the same manner, the inhibitory effect of Rap on the activation of p38 by IL-1 occurred at a point downstream of MyD88, IRAK, and TRAF6, since the activation of p38 MAPK by these components was inhibited by overexpressing active Rap1AV12, while neither MKK3 nor MKK6 were affected. Active RasVHa associated with IRAK, IRAK2, and TRAF6, but not MyD88. In addition we found a role for TAK-1 in the activation of p38 MAPK by IL-1, with TAK-1 also associating with active Ras. Our study suggests that upon activation Ras becomes associated with IRAK, Traf-6, and TAK-1, possibly aiding the assembly of this multiprotein signaling complex required for p38 MAPK activation by IL-1.
McDermott
Eva Pålsson
EP
Department of Biochemistry and Biotechnology Institute, Trinity College, Dublin 2, Ireland.
O'Neill
Luke A J
LA
D000818:Animals; D015153:Blotting, Western; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D004268:DNA-Binding Proteins; D015536:Down-Regulation; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005656:Fungal Proteins / Q000378:metabolism; D005799:Genes, Dominant; D006367:HeLa Cells; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism*; D053592:Interleukin-1 Receptor-Associated Kinases; D048371:MAP Kinase Kinase 3; D048669:MAP Kinase Kinase 6; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism*; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D011233:Precipitin Tests; D011485:Protein Binding; D011494:Protein Kinases / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction; D048029:TNF Receptor-Associated Factor 6; D014157:Transcription Factors / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured; D048051:p38 Mitogen-Activated Protein Kinases; D018631:ras Proteins / Q000378:metabolism; D000099151:MAP Kinase Kinase Kinase 7
D017871:Calcium-Calmodulin-Dependent Protein Kinases; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D005656:Fungal Proteins; D007375:Interleukin-1; D053592:Interleukin-1 Receptor-Associated Kinases; D048371:MAP Kinase Kinase 3; D048669:MAP Kinase Kinase 6; D020930:MAP Kinase Kinase Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D020928:Mitogen-Activated Protein Kinases; D011494:Protein Kinases; D011505:Protein-Tyrosine Kinases; D011506:Proteins; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D048029:TNF Receptor-Associated Factor 6; D014157:Transcription Factors; D048051:p38 Mitogen-Activated Protein Kinases; D018631:ras Proteins; D000099151:MAP Kinase Kinase Kinase 7; C052130:GAL4 protein, S cerevisiae; C482530:MAP2K3 protein, human; C482566:MAP2K6 protein, human; C482531:Map2k3 protein, mouse; C482567:Map2k6 protein, mouse