title: DEDD regulates degradation of intermediate filaments during apoptosis.
abstract: Apoptosis depends critically on regulated cytoskeletal reorganization events in a cell. We demonstrate that death effector domain containing DNA binding protein (DEDD), a highly conserved and ubiquitous death effector domain containing protein, exists predominantly as mono- or diubiquitinated, and that diubiquitinated DEDD interacts with both the K8/18 intermediate filament network and pro-caspase-3. Early in apoptosis, both cytosolic DEDD and its close homologue DEDD2 formed filaments that colocalized with and depended on K8/18 and active caspase-3. Subsequently, these filamentous structures collapsed into intracellular inclusions that migrated into cytoplasmic blebs and contained DEDD, DEDD2, active caspase-3, and caspase-3-cleaved K18 late in apoptosis. Biochemical studies further confirmed that DEDD coimmunoprecipitated with both K18 and pro-caspase-3, and kinetic analyses placed apoptotic DEDD staining prior to caspase-3 activation and K18 cleavage. In addition, both caspase-3 activation and K18 cleavage was inhibited by expression of DEDDDeltaNLS1-3, a cytosolic form of DEDD that cannot be ubiquitinated. Finally, siRNA mediated DEDD knockdown cells exhibited inhibition of staurosporine-induced DNA degradation. Our data suggest that DEDD represents a novel scaffold protein that directs the effector caspase-3 to certain substrates facilitating their ordered degradation during apoptosis.
authors.affiliation: The Ben May Institute for Cancer Research, University of Chicago, 924 E 57th Street, Chicago, IL 60637, USA.
authors.forename: Justine C
authors.initials: JC
authors.lastname: Lee
authors.forename: Olaf
authors.initials: O
authors.lastname: Schickling
authors.forename: Alexander H
authors.initials: AH
authors.lastname: Stegh
authors.forename: Robert G
authors.initials: RG
authors.lastname: Oshima
authors.forename: David
authors.initials: D
authors.lastname: Dinsdale
authors.forename: Gerald M
authors.initials: GM
authors.lastname: Cohen
authors.forename: Marcus E
authors.initials: ME
authors.lastname: Peter
mesh_terms: D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D002352:Carrier Proteins / Q000378:metabolism; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000502:physiology*; D053418:Death Domain Receptor Signaling Adaptor Proteins; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004792:Enzyme Precursors / Q000378:metabolism; D005260:Female; D006367:HeLa Cells; D006801:Humans; D002479:Inclusion Bodies / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure; D007382:Intermediate Filaments / Q000378:metabolism* / Q000648:ultrastructure; D047908:Intracellular Signaling Peptides and Proteins; D019169:Jurkat Cells; D007633:Keratins / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D009687:Nuclear Proteins / Q000378:metabolism; D034741:RNA, Small Interfering; D022661:RNA, Untranslated / Q000378:metabolism; D019311:Staurosporine / Q000494:pharmacology; D053221:TNF-Related Apoptosis-Inducing Ligand; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D051017:Apoptosis Regulatory Proteins; D002352:Carrier Proteins; C116096:DEDD protein, human; C450835:DEDD2 protein, human; D004268:DNA-Binding Proteins; D053418:Death Domain Receptor Signaling Adaptor Proteins; C486432:Dedd protein, mouse; D004791:Enzyme Inhibitors; D004792:Enzyme Precursors; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; D022661:RNA, Untranslated; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; C505654:Tnfsf10 protein, mouse; D014409:Tumor Necrosis Factor-alpha; D007633:Keratins; D004247:DNA; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; D019311:Staurosporine