title: Intracellular localization and transcriptional regulation of tumor necrosis factor (TNF) receptor-associated factor 4 (TRAF4).
abstract: To gain insight in the subcellular localization of tumor necrosis factor receptor-associated factor (TRAF4) we analyzed GFP chimeras of full-length TRAF4 and various deletion mutants derived thereof. While TRAF4-GFP (T4-GFP) was clearly localized in the cytoplasm, the N-terminal deletion mutant, T4(259-470), comprising the TRAF domain of the molecule, and a C-terminal deletion mutant consisting mainly of the RING and zinc finger domains of TRAF4 were both localized predominantly to the nucleus. Passive nuclear localization of T4(259-470) can be ruled out as the TRAF domain of TRAF4 was sufficient to form high molecular weight complexes. T4(259-470) recruited full-length TRAF4 into the nucleus whereas TRAF4 was unable to change the nuclear localization of T4(259-470). Thus, it seems that individual T4(259-470) mutant molecules are sufficient to direct the respective TRAF4-T4(259-470) heteromeric complexes into the nucleus. In cells forming cell-cell contacts, TRAF4 was recruited to the sites of contact via its C-TRAF domain. The expression of some TRAF proteins is regulated by the NF-kappaB pathway. Thus, we investigated whether this pathway is also involved in the regulation of the TRAF4 gene. Indeed, in primary T-cells and Jurkat cells stimulated with the NF-kappaB inducers TNF or phorbol 12-myristate 13-acetate (PMA), TRAF4-mRNA was rapidly up-regulated. In Jurkat T-cells deficient for I-kappaB kinase gamma (IKKgamma, also known as NEMO), an essential component of the NF-kappaB-inducing-IKK complex, induction of TRAF4 was completely inhibited. In cells deficient for RIP (receptor interactive protein), an essential signaling intermediate of TNF-dependent NF-kappaB activation, TNF-, but not PMA-induced up-regulation of TRAF4 was blocked. These data suggest that activation of the NF-kappaB pathway is involved in up-regulation of TRAF4 in T-cells.
mesh_terms: D002448:Cell Adhesion; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006801:Humans; D051550:I-kappa B Kinase; D066298:In Vitro Techniques; D019169:Jurkat Cells; D008164:Luminescent Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008213:Lymphocyte Activation; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D016328:NF-kappa B / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D053449:TNF Receptor-Associated Factor 4; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins; D015854:Up-Regulation
chemical_list: D008164:Luminescent Proteins; D016328:NF-kappa B; D011506:Proteins; D018124:Receptors, Tumor Necrosis Factor; D011993:Recombinant Fusion Proteins; D053449:TNF Receptor-Associated Factor 4; C506367:TRAF4 protein, human; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins; D049452:Green Fluorescent Proteins; D017346:Protein Serine-Threonine Kinases; C496559:CHUK protein, human; D051550:I-kappa B Kinase; C496560:IKBKB protein, human; C496565:IKBKE protein, human