MOLECULAR BASIS FOR CD40 SIGNALING MEDIATED BY TRAF3
[TRAF3_HUMAN] Defects in TRAF3 are the cause of susceptibility to herpes simplex encephalitis 3 (HSE3) [MIM:614849]. A rare complication of human herpesvirus 1 (HHV-1) infection, occurring in only a small minority of HHV-1 infected individuals. HSE is characterized by hemorrhagic necrosis of parts of the temporal and frontal lobes. Onset is over several days and involves fever, headache, seizures, stupor, and often coma, frequently with a fatal outcome. [TNR5_HUMAN] Defects in CD40 are the cause of immunodeficiency with hyper-IgM type 3 (HIGM3) [MIM:606843]. A rare immunodeficiency syndrome characterized by normal or elevated serum IgM levels with absence of IgG, IgA, and IgE. It results in a profound susceptibility to bacterial infections.
[TRAF3_HUMAN] Regulates pathways leading to the activation of NF-kappa-B and MAP kinases, and plays a central role in the regulation of B-cell survival. Part of signaling pathways leading to the production of cytokines and interferon. Required for normal antibody isotype switching from IgM to IgG. Plays a role T-cell dependent immune responses. Plays a role in the regulation of antiviral responses. Is an essential constituent of several E3 ubiquitin-protein ligase complexes. May have E3 ubiquitin-protein ligase activity and promote 'Lys-63'-linked ubiquitination of target proteins. Inhibits activation of NF-kappa-B in response to LTBR stimulation. Inhibits TRAF2-mediated activation of NF-kappa-B. Down-regulates proteolytic processing of NFKB2, and thereby inhibits non-canonical activation of NF-kappa-B. Promotes ubiquitination and proteasomal degradation of MAP3K14.      [TNR5_HUMAN] Receptor for TNFSF5/CD40LG.
Publication Abstract from PubMed
Tumor necrosis factor receptors (TNFR) are single transmembrane-spanning glycoproteins that bind cytokines and trigger multiple signal transduction pathways. Many of these TNFRs rely on interactions with TRAF proteins that bind to the intracellular domain of the receptors. CD40 is a member of the TNFR family that binds to several different TRAF proteins. We have determined the crystal structure of a 20-residue fragment from the cytoplasmic domain of CD40 in complex with the TRAF domain of TRAF3. The CD40 fragment binds as a hairpin loop across the surface of the TRAF domain. Residues shown by mutagenesis and deletion analysis to be critical for TRAF3 binding are involved either in direct contact with TRAF3 or in intramolecular interactions that stabilize the hairpin. Comparison of the interactions of CD40 with TRAF3 vs. TRAF2 suggests that CD40 may assume different conformations when bound to different TRAF family members. This molecular adaptation may influence binding affinity and specific cellular triggers.
Molecular basis for CD40 signaling mediated by TRAF3.,Ni CZ, Welsh K, Leo E, Chiou CK, Wu H, Reed JC, Ely KR Proc Natl Acad Sci U S A. 2000 Sep 12;97(19):10395-9. PMID:10984535
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.