Chk2 and REGgamma-dependent DBC1 regulation in DNA damage induced apoptosis.
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Magni M, Ruscica V, Buscemi G, Kim JE, Nachimuthu BT, Fontanella E, Delia D, Zannini L
Chk2 and REGgamma-dependent DBC1 regulation in DNA damage induced apoptosis.
Nucleic Acids Res. 2014 Dec 1;42(21):13150-60. doi: 10.1093/nar/gku1065. Epub 2014 Oct 31.
- PubMed ID
- 25361978 [ View in PubMed]
- Abstract
Human DBC1 (Deleted in Breast Cancer 1; KIAA1967; CCAR2) is a protein implicated in the regulation of apoptosis, transcription and histone modifications. Upon DNA damage, DBC1 is phosphorylated by ATM/ATR on Thr454 and this modification increases its inhibitory interaction with SIRT1, leading to p53 acetylation and p53-dependent apoptosis. Here, we report that the inhibition of SIRT1 by DBC1 in the DNA damage response (DDR) also depends on Chk2, the transducer kinase that is activated by ATM upon DNA lesions and contributes to the spreading of DNA damage signal. Indeed we found that inactivation of Chk2 reduces DBC1-SIRT1 binding, thus preventing p53 acetylation and DBC1-induced apoptosis. These events are mediated by Chk2 phosphorylation of the 11S proteasome activator REGgamma on Ser247, which increases REGgamma-DBC1 interaction and SIRT1 inhibition. Overall our results clarify the mechanisms underlying the DBC1-dependent SIRT1 inhibition and link, for the first time, Chk2 and REGgamma to the ATM-DBC1-SIRT1 axis.