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Human Daxx regulates Fas‐induced apoptosis from nuclear PML oncogenic domains (PODs)
Author(s) -
Torii Seiji,
Egan David A.,
Evans Ronald A.,
Reed John C.
Publication year - 1999
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/18.21.6037
Subject(s) - death associated protein 6 , biology , death domain , apoptosis , fas receptor , microbiology and biotechnology , transcription factor , caspase , fas ligand , programmed cell death , nuclear localization sequence , kinase , caspase 8 , nuclear protein , cancer research , gene , nucleus , genetics
Daxx was first identified as a protein that binds the cytosolic domain of Fas and links this receptor to an apoptosis pathway involving activation of Jun N‐terminal kinase (JNK). We show here that cells overexpressing the human homolog of Daxx (hDaxx) display enhanced sensitivity to apoptosis induced by Fas but not by several other cell death stimuli. hDaxx‐mediated enhancement of Fas‐induced apoptosis was correlated with accelerated activation of caspases but not with JNK induction. Although specifically enhancing Fas function, hDaxx does not bind Fas and instead is found in the nucleus where it localizes to PML oncogenic domains (PODs). Moreover, the hDaxx protein also exhibits the ability to repress transcription. Mutagenesis studies demonstrated a correlation between the localization of hDaxx to PODs and its ability to enhance Fas‐induced cell death. Arsenic trioxide (As 2 O 3 ), an agent that accentuates POD formation, collaborated synergistically with overexpression of hDaxx to increase cellular sensitivity to Fas‐induced apoptosis. Taken together, these findings argue that hDaxx promotes sensitivity to Fas from a nuclear location, probably by modulating the transcription of genes involved in Fas‐induced caspase activation and apoptosis.