Developing peptide inhibitors of Shp2 through a one-bead-one-compound approach.
Tomlinson, Kira Leigh.
- Shp2 is a protein tyrosine phosphatase that is mutated in Noonan syndrome and myeloid neoplasms, and aberrantly activated in HER-positive breast cancers and H. pylori-induced gastric cancer. Shp2 has been found to act upstream of a variety of growth factor and cytokine signaling pathways, but its role within the cell has not been fully elucidated. Potent and specific inhibitors of Shp2 are needed ... read moreto further investigate the role of Shp2 in these pathways and pathologies. This project aims to develop peptide inhibitors of the Shp2 catalytic domain through rational design followed by one-bead-one-compound (OBOC) libraries. Novel peptides were derived from a loop in the auto-inhibited conformation of Shp2 that provided structural elements to circumvent the obstacles of specificity and phosphotyrosine mimicry, which are common in phosphatase inhibitor design. To confer a similar loop structure, the peptides were conformationally restrained through thiol-bisalkylation chemistry. When tested in a DiFMUP inhibition assay, the linear peptide, with an IC50 of 3.51 μM, was a better inhibitor of the Shp2 PTP domain than the bisalkylated peptides, with IC50s ~20 μM. Goals for the immediate future of this project include testing a serine-containing derivative of the linear D’-derived peptide, performing a mini-mutagenesis study of the DY motif, and subjecting the linear D’-derived peptide to a phosphotyrosine ELISA assay. Further iterations of the D’-derived peptide will be explored using OBOC libraries to improve activity and specificity.read less