Abstract 1205 The mitochondrial ClpP protease: from basic principles to drug discovery

Mitochondrial matrix ClpP is a serine protease that forms a tetradecameric cylindrical structure. ClpP acts as a complex with the hexameric ATPase ClpX to form the ClpXP ATP-dependent protease. ClpXP is responsible for mitochondrial protein quality control through specific degradation of proteins involved in several metabolic processes. Furthermore, ClpP overexpression is required in many cancer cells to eliminate ROS-damaged proteins and to sustain oncogenesis. Targeting ClpP to dysregulate its function using small molecule agonists is a recent strategy in cancer therapy. Here, we describe the mechanism of function of ClpXP and the development of novel compounds that dysregulate the activity of the protease. Using X-ray crystallography, we found that these compounds bind at surface hydrophobic pockets of ClpP preventing ClpX interaction. N-terminome profiling of cancer cells upon treatment with one of these compounds revealed the global proteomic changes that arise and identified the structural motifs preferred for protein cleavage by compound-activated ClpP. Together, our studies provide the structural and molecular bases by which dysregulated ClpP affects cancer cell viability and proliferation. Canadian Institutes of Health Research (PJT-173345) Canadian Cancer Society Innovation Grant (Grant #706282)