Allosteric Site on SHIP2 Identified Through Fluorescent Ligand Screening and Crystallography: A Potential New Target for Intervention

J Med Chem. 2021 Apr 8;64(7):3813-3826. doi: 10.1021/acs.jmedchem.0c01944. Epub 2021 Mar 16.


Src homology 2 domain-containing inositol phosphate phosphatase 2 (SHIP2) is one of the 10 human inositol phosphate 5-phosphatases. One of its physiological functions is dephosphorylation of phosphatidylinositol 3,4,5-trisphosphate, PtdIns(3,4,5)P3. It is therefore a therapeutic target for pathophysiologies dependent on PtdIns(3,4,5)P3 and PtdIns(3,4)P2. Therapeutic interventions are limited by the dearth of crystallographic data describing ligand/inhibitor binding. An active site-directed fluorescent probe facilitated screening of compound libraries for SHIP2 ligands. With two additional orthogonal assays, several ligands including galloflavin were identified as low micromolar Ki inhibitors. One ligand, an oxo-linked ethylene-bridged dimer of benzene 1,2,4-trisphosphate, was shown to be an uncompetitive inhibitor that binds to a regulatory site on the catalytic domain. We posit that binding of ligands to this site restrains L4 loop motions that are key to interdomain communications that accompany high catalytic activity with phosphoinositide substrate. This site may, therefore, be a future druggable target for medicinal chemistry.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Allosteric Site
  • Amino Acid Sequence
  • Animals
  • Catalytic Domain
  • Cell Line, Tumor
  • Crystallography, X-Ray
  • Enzyme Inhibitors / metabolism
  • Enzyme Inhibitors / pharmacology
  • Fluoresceins / metabolism*
  • Fluorescent Dyes / metabolism*
  • Humans
  • Inositol Phosphates / metabolism*
  • Ligands
  • Mice
  • Molecular Docking Simulation
  • NIH 3T3 Cells
  • Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases / antagonists & inhibitors*
  • Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases / chemistry
  • Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases / metabolism*
  • Protein Binding


  • Enzyme Inhibitors
  • Fluoresceins
  • Fluorescent Dyes
  • Inositol Phosphates
  • Ligands
  • Inppl1 protein, mouse
  • Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases