Orozco Research Project Summary

The overall goal of this project is to boost anti-viral immunity by inhibiting the protein tyrosine phosphatase non receptor 22 (PTPN22/Ptpn22) encoded enzyme Lyp (PEP in mice). Our hypothesis is that targeting Lyp/PEP C-terminal binding domain rather than the N-terminal enzymatic pocket will; 1- increase specificity and 2- chemically replicate the altered function caused by a commonly expressed PTPN22 allele (rs24766010), which causes an arginine (Arg) to tryptophan (Trp) amino acid substitution in the C-terminal region of Lyp/PEP and disrupts binding. In myeloid cells, N-terminal mutations rendering ‘enzymatically dead’ Lyp/PEP compared to the health-relevant mutation in the C-terminal binding domain (rs24760010) can have different biological impact. We have previously shown that mice harboring this PEP Arg→Trp Cterminal mutation have enhanced anti-viral immunity and can clear persistent virus infection. Now, we aim to therapeutically target PEP to achieve a comparable phenotype. This project utilizes the use of multiple CoBRE funded and non-CoBRE funded cores at the University of Kansas (KU). In brief, we will employ the protein production group to purify full length, N-terminal, and C- Terminal region of PEP. Then, the Infectious Disease Assay Development (IDAD) core will screen a compound library against these various PEP constructs. After identifying the compound of interest, this data will be submitted to the Computational Chemical Biology (CCB) core to computationally define these potential inhibitors. Further, the CCB core will work to rationally design a peptide based on the available structure of the P1 binding domain of PEP to binding partner Csk. Alongside these computational analyses, my lab will biologically validate the compounds evaluating anti-viral function in various immune cells, such as cytokine production, using spectral flow cytometry in the new Immunology Core. We will also molecularly assess the binding capacity of PEP to common protein partners. Future studies will submit the top compound(s) to the Synthetic Chemical Biology (SCB) core to be chemically stabilized and modified for in vivo experiments addressing anti-viral immunity. Discovery of such compounds results in a novel tool to further understand the role of Lyp/PEP during disease and potentially lead to a new therapeutic to better treat individual’s suffering from chronic infectious diseases.