Allosteric site on SHIP2 identified through fluorescent ligand screening and crystallography: a potential new target for intervention

Hayley Whitfield, Andrew M. Hemmings, Stephen J. Mills, Kendall Baker, Gaye White, Stuart Rushworth, Andrew M. Riley, Barry V. L. Potter, Charles A. Brearley

Research output: Contribution to journalArticlepeer-review

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Abstract

Src Homology 2 domain-containing inositol phosphate phosphatase 2 (SHIP2) is one of ten 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.
Original languageEnglish
Pages (from-to)3813–3826
Number of pages14
JournalJournal of Medicinal Chemistry
Volume64
Issue number7
Early online date16 Mar 2021
DOIs
Publication statusPublished - 8 Apr 2021

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