Project Summary: Probes, Inhibitors, and PROTACs (PIP) Core The overarching mission of the PIP Core is to use sophisticated chemistry and mass spectrometry for development of small molecules that facilitate molecular target discovery and development. Genetic methods are routinely used to identify, develop, and validate molecular targets. These methods rely on altering the DNA or RNA sequences of the protein target. However, drug discovery relies on manipulating the function of the corresponding proteins using small molecules. Often the results obtained through these complementary strategies do not correlate.1 The incongruence associated with the results from these orthogonal approaches can be attributed to the complex biology that is dependent on multiple functions i.e., enzymatic and scaffolding, associated with the protein target. Modulating protein levels by altering the nucleic acids eliminates all the target protein functions. However small molecule modulators can be tuned to induce either domain specific effects (reversible or irreversible) or removal of the entire protein (PROTAC) with exquisite temporal control. These could be tagged with photoactivatable or fluorescent molecules, or biotin to enable target identification and validation, study mechanism of action, or characterize the associated interactome. In addition to the design and synthesis of above types of small molecules, the PIP Core will also provide scale up services (mg to g) for additional experiments such as in vivo validation of targets and hit-to-lead optimization studies to generate structure activity relationship (SAR) data. Mass spectrometry will be used to characterize the impact of these compounds on the proteome through quantitative analysis of proteins and posttranslational or chemical modifications to validate mechanism of action and compensatory features that may contribute to drug resistance. The Core will be led by Drs. Natarajan and Woods, who will bring complementary expertise to the PIP Core. Dr. Natarajan has extensive expertise in developing probes, inhibitors, and PROTACs, using cutting edge chemistry methods. Dr. Woods has extensive experience using mass spectrometry as a platform for delineating protein- protein interactions, posttranslational modifications, and multivariate biomarkers of cancer response to therapy. PIP Core services will be extensively utilized by CMTDD Research Project Leaders (RPLs), CMTDD members and University researchers at large.