title: Upon intracellular processing, the C-terminal death domain-containing fragment of the p53-inducible PIDD/LRDD protein translocates to the nucleoli and interacts with nucleolin.
abstract: The p53-inducible and death domain-containing PIDD/LRDD protein has been described as an adaptor protein, which forms large protein complexes with RAIDD, another death domain-containing protein, leading to recruitment, and activation of the initiator caspase-2, and p53-mediated apoptosis. Here, we describe in further detail the proteolytic processing of PIDD/LRDD that occurs in healthy cells before induction of apoptosis. We could demonstrate that the C-terminal fragment containing the PIDD death domain shuttles into the nucleoli. This translocation is mediated by or leads to the interaction of the PIDD death domain with nucleolin, a protein important for rRNA processing within nucleoli and possibly involved in the DNA damage response. Ectopically expressed LRDD and endogenous nucleolin co-localized within the nucleoli, and overexpression of both full-length LRDD and the LRDD death domain sensitized cells for UV-induced apoptosis. When expressed alone, the PIDD/LRDD death domain tended to form large filamentous structures resembling so-called death filaments. The functional consequences of the identified PIDD/nucleolin interaction remain to be elucidated, but may be related to a recently discovered new role for PIDD in the activation of NF-kappaB upon genotoxic stress.
authors.affiliation: Chemotherapeutisches Forschungsinstitut Georg-Speyer-Haus, Paul-Ehrlich-Strasse 42-44, D-60596 Frankfurt, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Pick
authors.forename: Susanne
authors.initials: S
authors.lastname: Badura
authors.forename: Susanne
authors.initials: S
authors.lastname: Bösser
authors.forename: Martin
authors.initials: M
authors.lastname: Zörnig
mesh_terms: D001665:Binding Sites; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D053418:Death Domain Receptor Signaling Adaptor Proteins; D006801:Humans; D007424:Intracellular Fluid / Q000378:metabolism; D007668:Kidney / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport / Q000502:physiology; D016601:RNA-Binding Proteins / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D000097796:Nucleolin
chemical_list: D002352:Carrier Proteins; D053418:Death Domain Receptor Signaling Adaptor Proteins; D010446:Peptide Fragments; D010750:Phosphoproteins; D016601:RNA-Binding Proteins; D016159:Tumor Suppressor Protein p53; D000097796:Nucleolin; C485896:PIDD1 protein, human