title: Nuclear and cytoplasmic shuttling of TRADD induces apoptosis via different mechanisms.
abstract: The adapter protein tumor necrosis factor receptor (TNFR)1-associated death domain (TRADD) plays an essential role in recruiting signaling molecules to the TNFRI receptor complex at the cell membrane. Here we show that TRADD contains a nuclear export and import sequence that allow shuttling between the nucleus and the cytoplasm. In the absence of export, TRADD is found within nuclear structures that are associated with promyelocytic leukemia protein (PML) nuclear bodies. In these structures, the TRADD death domain (TRADD-DD) can activate an apoptosis pathway that is mechanistically distinct from its action at the membrane-bound TNFR1 complex. Apoptosis by nuclear TRADD-DD is promyelocytic leukemia protein dependent, involves p53, and is inhibited by Bcl-xL but not by caspase inhibitors or dominant negative FADD (FADD-DN). Conversely, apoptosis induced by TRADD in the cytoplasm is resistant to Bcl-xL, but sensitive to caspase inhibitors and FADD-DN. These data indicate that nucleocytoplasmic shuttling of TRADD leads to the activation of distinct apoptosis mechanisms that connect the death receptor apparatus to nuclear events.
authors.affiliation: Department of Cancer Biology and Comprehensive Cancer Center, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Morgan
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Thorburn
authors.forename: Pier Paolo
authors.initials: PP
authors.lastname: Pandolfi
authors.forename: Andrew
authors.initials: A
authors.lastname: Thorburn
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002467:Cell Nucleus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D005260:Female; D006801:Humans; D051379:Mice / Q000196:embryology; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism*; D016415:Sequence Alignment; D015398:Signal Transduction; D053199:TNF Receptor-Associated Death Domain Protein; D047990:TNF Receptor-Associated Factor 1; D014407:Tumor Cells, Cultured; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D005231:Fatty Acids, Unsaturated; D011506:Proteins; D018124:Receptors, Tumor Necrosis Factor; D053199:TNF Receptor-Associated Death Domain Protein; D047990:TNF Receptor-Associated Factor 1; C481226:Tradd protein, mouse; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins; D016159:Tumor Suppressor Protein p53; C038753:leptomycin B