Grant: Project Grant

The cellular DNA damage repair response protects us from genotoxins and maintains the stability of our genome. When errors accumulate in the repair machinery, we are prone to both cancer and age-associated diseases. A functioning response is essential even for cancer cells, so a standard therapeutic approach is to overwhelm the repair response using "blunt instruments" such as ionizing radiation and genotoxic drugs. This level of targeting is crude by any measure, leading to unwanted toxicities and an incomplete response. The applied goal of our project is to better understand how mechanisms of DNA repair work, in order to sensitize cancer cells to existing therapies. While DNA damage takes many forms, Double Strand Breaks (DSBs) are particularly dangerous and their repair machinery is a compelling target for anticancer therapy. The response to a DSB involves interacting mechanisms that generate different repair outcomes. Our proposal seeks to establish the structural and functional properties of a master end-sensing complex that ultimately determines how the repair program unfolds. The key protein involved in this end-sensing complex is a massive kinase called DNA-PKcs. One of our major goals is to determine how this protein responds to the damage event itself, not just the signalling events that initiate them. They must work together to determine repair outcomes. To do this, we will use cutting-edge structural techniques, including Cryo-Electron Microscopy, Hydrogen-Deuterium Exchange Mass Spectrometry and Crosslinking Mass Spectrometry. We have assembled an excellent team of collaborators to assist in translating molecular/structural insights into mechanistic validations at the cellular level, in order to define new strategies for targeting cancer.