Phosphorylation-dependent Lys63-linked polyubiquitination of Daxx is essential for sustained TNF-α-induced ASK1 activation

Yayoi Fukuyo, Tetsuya Kitamura, Masahiro Inoue, Nobuko T. Horikoshi, Ryuji Higashikubo, Clayton R. Hunt, Anny Usheva, Nobuo Horikoshi*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Apoptosis signal-regulating kinase 1 (ASK1) is a key regulatory kinase in the proapoptotic response to various stresses. ASK1 phosphorylation of Daxx, an ASK1 activator protein, increases Daxx accumulation in cells and further enhances ASK1 activity through a positive feedback mechanism. Here, we show that ASK1-dependent phosphorylation of Daxx induces Lys63 (K63)-linked polyubiquitination on Lys122 of Daxx. Polyubiquitination is dispensable for Daxx accumulation or Daxx interaction with ASK1 because mutant Daxx deficient in polyubiquitin still exhibits ASK1-dependent accumulation and interaction with cellular ASK1. However, K63-linked Daxx polyubiquitination is required for tumor necrosis factor-α (TNF-α)-induced activation of ASK1. Therefore, K63-linked polyubiquitination of Daxx functions as a molecular switch to initiate and amplify the stress kinase response in the TNF-α signaling pathway.

Original languageEnglish (US)
Pages (from-to)7512-7517
Number of pages6
JournalCancer Research
Issue number19
StatePublished - Oct 1 2009

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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