An unconventional gatekeeper mutation sensitizes inositol hexakisphosphate kinases to an allosteric inhibitor

• Published in: eLife Vol. 12
• Main Authors: Aguirre, Tim, Dornan, Gillian L, Hostachy, Sarah, Neuenschwander, Martin, Seyffarth, Carola, Haucke, Volker, Schütz, Anja, von Kries, Jens Peter, Fiedler, Dorothea
• Format: Journal Article
• Language: English
• Published: Cambridge eLife Sciences Publications Ltd 16.10.2023; eLife Sciences Publications, Ltd
• Subjects: allosteric inhibitor; Allosteric properties; analog-sensitive; Binding sites; Biochemistry and Chemical Biology; Enzymes; Hydrogen-deuterium exchange; Inositol; inositol phosphate; Isoenzymes; kinase; Kinases; Mass spectroscopy; Metabolism; Mutation; Phenotypes; Proteins; Valine
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.88982

Inositol hexakisphosphate kinases (IP6Ks) are emerging as relevant pharmacological targets because a multitude of disease-related phenotypes has been associated with their function. While the development of potent IP6K inhibitors is gaining momentum, a pharmacological tool to distinguish the mammalian isozymes is still lacking. Here, we implemented an analog-sensitive approach for IP6Ks and performed a high-throughput screen to identify suitable lead compounds. The most promising hit, FMP-201300, exhibited high potency and selectivity toward the unique valine gatekeeper mutants of IP6K1 and IP6K2, compared to the respective wild-type (WT) kinases. Biochemical validation experiments revealed an allosteric mechanism of action that was corroborated by hydrogen deuterium exchange mass spectrometry measurements. The latter analysis suggested that displacement of the α C helix, caused by the gatekeeper mutation, facilitates the binding of FMP-201300 to an allosteric pocket adjacent to the ATP-binding site. FMP-201300 therefore serves as a valuable springboard for the further development of compounds that can selectively target the three mammalian IP6Ks; either as analog-sensitive kinase inhibitors or as an allosteric lead compound for the WT kinases.