Abstract
SHP2 phosphatase is a positive transducer of growth factor and cytokine signaling. SHP2 is also a bona fide oncogene; gain-of-function SHP2 mutations leading to increased phosphatase activity cause Noonan syndrome, as well as multiple forms of leukemia and solid tumors. We report that tautomycetin (TTN), an immunosuppressor in organ transplantation, and its engineered analog TTN D-1 are potent SHP2 inhibitors. TTN and TTN D-1 block T cell receptor-mediated tyrosine phosphorylation and ERK activation and gain-of-function mutant SHP2-induced hematopoietic progenitor hyperproliferation and monocytic differentiation. Crystal structure of the SHP2⋅TTN D-1 complex reveals that TTN D-1 occupies the SHP2 active site in a manner similar to that of a peptide substrate. Collectively, the data support the notion that SHP2 is a cellular target for TTN and provide a potential mechanism for the immunosuppressive activity of TTN. Moreover, the structure furnishes molecular insights upon which therapeutics targeting SHP2 can be developed on the basis of the TTN scaffold.