InVivo_DDR_ADPR · Decoding the DNA damage signalling in C. elegans by proteomic analyses of ADP-ribosylation

Decoding the DNA damage signalling in C. elegans by proteomic analyses of ADP-ribosylation

Preservation of genome integrity and stability is critical for survival and propagation of individuals and species. Organisms have thus evolved rapid and efficient mechanisms –collectively termed the DNA damage response (DDR)– to combat threats posed by DNA damage. Among these, the post-translational modification (PTM) ADP-ribosylation (ADPr) plays a decisive role in effective DDR. What is the issue being addressed? Although much is known about the relevance of ADPr upon DNA injury, the underlying molecular mechanisms are still poorly understood. In contrast to the restricted amino acid specificities of most PTMs, nearly all chemically reactive amino acid side chains have been reported as targets of ADPr. Functional and mechanistic understanding of ADPr requires knowledge of its target amino acids and the exact conjugation sites within the substrate proteins. What are the overall objectives? The most challenging and innovative goal of this proposal is to elucidate the molecular mechanisms of ADPr in the DNA damage response. Initially, we aim to develop a mass spectrometric approach for unambiguous and unbiased ADPr site mapping in endogenous samples. Then, we will profile ADP-ribosylated peptides during DDR in cells. Finally, we aim to advance the understanding of the underlying molecular mechanisms as a prelude to improving prevention, diagnosis and treatment of many common health problems. Why is it important? Understanding the molecular mechanisms underlying such a complex biological process as ADPr will provide new insights for improved treatment of DNA damage-related diseases, including cancer. This is an ambitious, innovative, cross-disciplinary project at the forefront of two exciting fields, biology and proteomics. Conclusions With our unambiguous and unbiased ADPr site mapping, we uncovered serine ADPr (Ser-ADPr) as a novel protein modification and described the molecular mechanisms by characterizing the “writers” (proteins responsible for the attachment of the modification onto target proteins) and the “eraser” (protein responsible for the removal of the modification from ADP-ribosylated proteins). We have also shown that Ser-ADPr is a widespread modification and that is the major form of ADPr under DNA damage. Our findings have challenged 50 years of consensus understanding on ADPr biology and have opened a large and novel research area into how ADPr regulates the DNA damage response, chromatin dynamics and transcription.

Data: CORDIS, © European Union