Shu-Fang Hsu
Institute of Biological Chemistry, Academia Sinica, Taiwan
Title: Hybrid methods reveal the structural architecture of PTPN3-p38 γ active-state complex
Biography
Biography: Shu-Fang Hsu
Abstract
PTPN3 (also known as PTPH1) cooperate to promote Ras-induced oncogenesis in human colorectal cancer. Comprehensive
structural information on the PTPN3-p38γ interaction is critical for structure-based drug design as a new means in anticancer
therapy.
Methodology & Th eoretical Orientation: In order to obtain the architecture features of PTPN3-p38γ active-state complex,
a hybrid method combining small-angle x-ray scattering (SAXS), chemical cross-linking coupled to mass spectrometry (CXMS),
hydrogen deuterium exchange mass spectrometry (HDX-MS), and x-ray crystallography were adopted.
Findings: To build the molecular architecture of PTPN3-p38γ active-state complex, the phosphatase domain of PTPN3 in its
substrate trapping mutant form was used to interact with the phosphorylated p38γ in vitro. Isothermal titration calorimetry
(iTC) analysis showed that PTPN3 binds to phosphorylated p38γ in a submicromolar affi nity, suggesting the formation
of a stable complex. CX-MS analysis unraveled the close proximity between the catalytic site of PTPN3 and the activation
loop of phospho-p38γ. HDX-MS results further demonstrated that the glutamic acid-containing loop (E-loop) and the
phosphotyrosine recognition loop (pY loop) of PTPN3 play a critical role in recruiting p38γ as a substrate during catalysis.
Preliminary crystals of PTPN3-p38γ active-state complex were obtained and the microseeding technique was applied to
optimize the crystal formation.
Conclusion & Signifi cance: Atomic structure of PTPN3-p38γ active-state complex may reveal the molecular features for the
design of new drug against the progression of colorectal cancer.