Spotting new DNA damage-responsive chromatin-binding proteins.

In response to DNA damage, cells initiate multiple repair mechanisms that all contribute to the survival of both the cell and the organism. These responses are numerous and variable, and can include cell cycle arrest, transcriptional activation of DNA repair genes and relocalization of repair proteins to sites of DNA damage. If all else fails, in multicellular organisms the initiation of apoptosis is also a potential cellular response to DNA damage. Despite a wealth of information about these events, it is clear that we do not yet have a comprehensive picture of the cellular responses to DNA damage. In this issue of the Biochemical Journal, a proteomics approach was used by Lee et al. to identify proteins that bind to chromatin in a DNA damage-inducible manner. The proteins identified, nucleophosmin, hnRNP C1 (heterogeneous nuclear ribonucleoprotein C1) and hnRNP C2, were proteins that would not necessarily have been predicted to behave this way. These studies have the potential to be extended and contribute to our knowledge of the cellular response to DNA damage.