Investigating the regulation and substrate processing of ADAMTS13 and ADAMTS7 metalloproteases

Project Summary This MIRA proposal aims to uncover the regulatory mechanisms and substrates for metalloproteases in the ADAMTS (A Disintegrin And Metalloprotease with ThromboSpondin motifs) family. These proteases are thought to be involved in many biological processes and some members are known to contribute to important human diseases. The current study focuses mainly on two members of the ADAMTS family, ADAMTS13 and ADAMTS7. Project 1 will investigate the allosteric regulation of ADAMTS13, an important regulator of blood clotting. I recently discovered that ADAMTS13 adopts a quiescent closed conformation and becomes allosterically activated by its substrate, Von Willebrand Factor (VWF). This proposal outlines a mechanistic approach to study how allosteric regulation is maintained within ADAMTS13 and disrupted by its interaction with VWF. Leveraging functional, kinetic, structural and bioinformatic analyses, this project sets to identify the key structural elements of allosteric regulation in ADAMTS13. The outcomes from this work will improve our understanding of inherited and acquired blood clotting disorders caused by defects in ADAMTS13. I also anticipate that our investigation of ADAMTS13 will serve as a model to study the regulation of other ADAMTS proteases. Project 2 focuses on ADAMTS7, which is known to contribute to coronary artery disease by promoting atherosclerosis and inflammation. However, the substrate targets of ADAMTS7 and its biochemical properties remain poorly understood. Previous attempts to address these research questions led to conflicting reports in the literature, likely due to the poor quality of reagents and tools available to study this novel protease. To circumvent these challenges, we will utilize novel methods in proteomics, enzymology, and protein-protein interactions to delineate biochemical properties and ideal substrates for ADAMTS7. Newly identified substrates will form the basis of novel biochemical tools to investigate ADAMTS7 activity and are necessary for future research goals to screen for small molecule inhibitors of ADAMTS7 that may have translational applications. Summarily, the study of ADAMTS13 and ADAMTS7 enzyme catalysis and regulation lay a foundation for our understanding of thrombotic and bleeding disorders and cardiovascular and inflammatory diseases, and these outcomes can be applied to study other ADAMTS proteases.