title: Activation of p42mapk/erk2 following engagement of tumor necrosis factor receptor CD120a (p55) in mouse macrophages.
abstract: Cross-linking of the dichotomous cell surface receptors for TNF-alpha (CD120a (p55) and CD120b (p75)) induces the activation of a variety of macrophage responses that mediate the role of this cell in inflammation and host defense. Although significant progress has been made in understanding the role that lipid second messengers play in mediating the action(s) of this multifunctional cytokine, less is known about the role of specific kinases in TNF-alpha-initiated signaling. We show that exposure of mouse macrophages to TNF-alpha stimulates a rapid and transient tyrosine phosphorylation and activation of p42mapk/erk2. By contrast, p44mapk/erk1 was found to be constitutively phosphorylated, with minimal further response to TNF-alpha. To investigate the use of CD120a (p55) and CD120b (p75) in the activation of p42mapk/erk2 in mouse macrophages, we determined the effects of blocking Ab on the activation of p42mapk/erk2 in response to TNF-alpha. In addition, we independently cross-linked each receptor with specific agonistic Ab, which have previously been shown to mimic the effects of TNF-alpha. Collectively, the results from these experiments indicate that cross-linking of CD120a (p55), but not that of CD120b (p75), was both necessary and sufficient for the activation of p42mapk/erk2 in mouse macrophages.
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: D W
authors.initials: DW
authors.lastname: Riches
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000276:immunology / Q000494:pharmacology; D015703:Antigens, CD / Q000276:immunology / Q000502:physiology*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002478:Cells, Cultured; D002852:Chromatography, Ion Exchange; D004789:Enzyme Activation; D008264:Macrophages / Q000502:physiology*; D051379:Mice; D008809:Mice, Inbred C3H; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011940:Receptor Aggregation; D018124:Receptors, Tumor Necrosis Factor / Q000276:immunology / Q000502:physiology*; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D000906:Antibodies; D015703:Antigens, CD; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D014409:Tumor Necrosis Factor-alpha; D011505:Protein-Tyrosine Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases