An 11-amino acid sequence in the cytoplasmic domain of CD40 is sufficient for activation of c-Jun N-terminal kinase, activation of MAPKAP kinase-2, phosphorylation of I kappa B alpha, and protection of WEHI-231 cells from anti-IgM-induced growth arrest.
We have previously shown that CD40 causes strong activation of the c-Jun N-terminal kinase (JNK), the p38 mitogen-activated protein kinases (MAPK) and MAPKAP kinase-2, a downstream target of p38 MAPK. To identify signaling motifs in the CD40 cytoplasmic domain that are responsible for activation of these kinases, we have created a set of 11 chimeric receptors consisting of the extracellular and transmembrane domains of CD8 fused to portions of the murine CD40 cytoplasmic domain. These chimeric receptors were expressed in WEHI-231 B lymphoma cells. We found that amino acids 35-45 of the CD40 cytoplasmic domain constitute an independent signaling motif that is sufficient for activation of the JNK and p38 MAPK pathways, as well as for induction of I kappa B alpha phosphorylation and degradation. Amino acids 35-45 were also sufficient to protect WEHI-231 cells from anti-IgM-induced growth arrest. This is the same region of CD40 required for binding the TNF receptor-associated factor-2 (TRAF2), TRAF3, and TRAF5 adapter proteins. These data support the idea that one or more of these TRAF proteins couple CD40 to the kinase cascades that activate NF-kappa B, JNK, and p38 MAPK.
Sutherland
C L
CL
Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada.
Krebs
D L
DL
Gold
M R
MR
D000595:Amino Acid Sequence; D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000502:physiology*; D001483:Base Sequence; D001665:Binding Sites / Q000276:immunology; D019013:CD40 Antigens / Q000235:genetics / Q000502:physiology*; D016827:CD8 Antigens / Q000235:genetics; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002455:Cell Division / Q000276:immunology; D003593:Cytoplasm / Q000737:chemistry / Q000201:enzymology / Q000276:immunology*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004789:Enzyme Activation / Q000276:immunology; D006801:Humans; D020672:I-kappa B Proteins; D007075:Immunoglobulin M / Q000276:immunology*; D047908:Intracellular Signaling Peptides and Proteins; D048031:JNK Mitogen-Activated Protein Kinases; D051379:Mice; D020928:Mitogen-Activated Protein Kinases; D008969:Molecular Sequence Data; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism; D010446:Peptide Fragments / Q000502:physiology; D010449:Peptide Mapping; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000096:biosynthesis / Q000235:genetics; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000276:immunology; D015398:Signal Transduction / Q000276:immunology; D048029:TNF Receptor-Associated Factor 6; D013912:Threonine / Q000502:physiology; D014407:Tumor Cells, Cultured; D000099190:MAP-Kinase-Activated Kinase 2
D000888:Antibodies, Anti-Idiotypic; D019013:CD40 Antigens; D016827:CD8 Antigens; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D007075:Immunoglobulin M; D047908:Intracellular Signaling Peptides and Proteins; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B; D010446:Peptide Fragments; D017346:Protein Serine-Threonine Kinases; D011506:Proteins; D011948:Receptors, Antigen, T-Cell; D018124:Receptors, Tumor Necrosis Factor; D011993:Recombinant Fusion Proteins; D048029:TNF Receptor-Associated Factor 6; D013912:Threonine; D000099190:MAP-Kinase-Activated Kinase 2; C067361:CD8 receptor; C000606204:NFKBIA protein, human; C000606205:Nfkbia protein, mouse; C044203:anti-IgM