A cytoplasmic ATM-TRAF6-cIAP1 module links nuclear DNA damage signaling to ubiquitin-mediated NF-κB activation

Michael Hinz, Michael Stilmann, Seda Çöl Arslan, Kum Kum Khanna, Gunnar Dittmar, Claus Scheidereit*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

225 Citations (Scopus)

Abstract

As part of the genotoxic stress response, cells activate the transcription factor NF-κB. The DNA strand break sensor poly(ADP-ribose)-polymerase-1 (PARP-1) and the kinase ataxia telangiectasia mutated (ATM) act as proximal signal mediators. PARP-1 assembles a nucleoplasmic signalosome, which triggers PIASy-mediated IKKγ SUMOylation. ATM-dependent IKKγ phosphorylation and subsequent ubiquitination were implicated to activate the cytoplasmic IκB kinase (IKK) complex by unknown mechanisms. We show that activated ATM translocates in a calcium-dependent manner to cytosol and membrane fractions. Through a TRAF-binding motif, ATM activates TRAF6, resulting in Ubc13-mediated K63-linked polyubiquitin synthesis and cIAP1 recruitment. The ATM-TRAF6-cIAP1 module stimulates TAB2-dependent TAK1 phosphorylation. Both nuclear PARP-1- and cytoplasmic ATM-driven signaling branches converge at the IKK complex to catalyze monoubiquitination of IKKγ at K285. Our data indicate that exported SUMOylated IKKγ acts as a substrate. IKKγ monoubiquitination is a prerequisite for genotoxic IKK and NF-κB activation, but also promotes cytokine signaling.

Original languageEnglish
Pages (from-to)63-74
Number of pages12
JournalMolecular Cell
Volume40
Issue number1
DOIs
Publication statusPublished - 8 Oct 2010
Externally publishedYes

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