title: Activation of p38mapk, MKK3, and MKK4 by TNF-alpha in mouse bone marrow-derived macrophages.
abstract: TNF-alpha regulates the expression of many proinflammatory and profibrogenic gene products in macrophages, and hence plays a vital role in controlling the inflammatory response. We have shown previously that exposure of macrophages to TNF-alpha stimulates the activation of members of the mitogen-activated protein kinase (MAPK) family. In this study, we have investigated the mechanism of activation of the p38mapk by TNF-alpha in mouse bone marrow-derived macrophages. Exposure to TNF-alpha resulted in the activation of p38mapk, as measured by 1) the trans-phosphorylation of recombinant activating transcription factor-2 substrate by immunoprecipitated p38mapk and 2) specific tyrosine phosphorylation of immunoprecipitated p38mapk. In addition, selective ligation of the TNF-alpha receptor CD120a (p55) with human TNF-alpha was sufficient to induce p38mapk activation. Using an in vitro kinase assay with recombinant kinase-inactive p38mapk as substrate in the presence of [gamma-32P]ATP, the upstream kinases MKK3 (mitogen-activated protein kinase kinase 3) and MKK4 were found to be activated in response to TNF-alpha. These findings suggest that TNF-alpha transiently phosphorylates and activates the three members of the MAPK family, namely p42(mapk/erk2), p46 c-Jun amino-terminal kinase/stress-activated protein kinase (JNK/SAPK), and p38mapk following cross-linking of CD120a (p55), and that MKK3 and MKK4 are capable of phosphorylating p38mapk.
authors.affiliation: Department of Pediatrics, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206, USA.
authors.forename: B W
authors.initials: BW
authors.lastname: Winston
authors.forename: E D
authors.initials: ED
authors.lastname: Chan
authors.forename: G L
authors.initials: GL
authors.lastname: Johnson
authors.forename: D W
authors.initials: DW
authors.lastname: Riches
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000276:immunology* / Q000378:metabolism; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000276:immunology / Q000378:metabolism*; D002478:Cells, Cultured; D006801:Humans; D048371:MAP Kinase Kinase 3; D048670:MAP Kinase Kinase 4; D008262:Macrophage Activation / Q000187:drug effects*; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D008809:Mice, Inbred C3H; D020929:Mitogen-Activated Protein Kinase Kinases; D020928:Mitogen-Activated Protein Kinases; D017346:Protein Serine-Threonine Kinases / Q000276:immunology / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000276:immunology / Q000378:metabolism*; D015398:Signal Transduction / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D014409:Tumor Necrosis Factor-alpha; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048371:MAP Kinase Kinase 3; D048670:MAP Kinase Kinase 4; C482530:MAP2K3 protein, human; C482559:MAP2K4 protein, human; C482531:Map2k3 protein, mouse; C482562:Map2k4 protein, mouse; D020929:Mitogen-Activated Protein Kinase Kinases