Induced-Proximity Platform to Control Cellular Signaling and Proteostasis

Research Plan: Recently, our approach to therapeutically targeting proteins has changed from directly inhibiting their function to inducing proximity with specific cellular component to promote desired interactions. The best- known example of these are Proteolysis-Targeting-Chimeras (PROTACs), whose success has thus expanded the druggable proteome. However, issues with recruiting active enzymes and avoiding the formation of resistance mutations has motivated us to develop a new class of proximity-inducing compounds termed GRoup- transfer chimeras for Inducing Proximity (GRIPs). GRIPs repurpose well-characterized inhibitors by ‘‘hijacking’’ the nucleophilicity of side chains proximal to inhibitor binding pockets to generate enzymes that recruit and edit a programmed target of choice. During the K99 phase, we will expand the design of GRIPs into a generic and modular platform that can be rapidly applied to recruit any kinase for targeted phosphorylation, which holds promise for diverse therapeutic outcomes and gain-of-function protein editing. We will apply these GRIPs to control cellular signaling, effectively switching it on/off via induced, targeted phosphorylation. We will also use CRISPR suppressor scanning to benchmark the resistance profile of GRIPs against traditional inhibitors. During the R00 phase, we will protect GRIPs from acquired resistance due to the downregulation of the targeted enzymes to degrade a target protein without engaging E3 complexes. Here, we will repurpose proteasomal and unfoldase inhibitors to induce proximity with high-value proteins such as KRAS. Training Plan: Under the guidance of my mentor, we have meticulously designed a comprehensive five-year training plan to equip me with the necessary skills and knowledge to be an effective mentor and independent researcher. It includes hands-on experience with cutting-edge experimental techniques, such as BLI/SPR, CRISPR suppressor scanning, and quantitative global proteomics, which are crucial for the successful completion of the proposal and for conducting high-quality research in my laboratory. Additionally, I will enhance my understanding of the field by attending classes, seminars, conferences, and workshops that were chosen to improve my leadership skills and facilitate a successful transition to an independent faculty position. Project Number: 1K99GM159057-01 | Fiscal Year: 2025 | NIH Institute/Center: National Institute of General Medical Sciences (NIGMS) | Principal Investigator: Endri Karaj | Institution: BROAD INSTITUTE, INC., CAMBRIDGE, MA | Award Amount: $118,242 | Activity Code: K99 | Study Section: Special Emphasis Panel[ZGM1 TWD-A (KR)] View on NIH RePORTER: https://reporter.nih.gov/project-details/11114520