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

Aguirre, T.; Hostachy, S.; Dornan, G. L.; Neuenschwander, M.; Seyffarth, C.; Haucke, V.; Schuetz, A.; von Kries, J. P.; Fiedler, D.

doi:10.1101/2023.04.26.538378

bioRxiv · 10.1101/2023.04.26.538378

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

Aguirre, T.·Hostachy, S.·Dornan, G. L.·Neuenschwander, M.·Seyffarth, C.·Haucke, V.·Schuetz, A.·von Kries, J. P.·Fiedler, D.

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Abstract

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 towards the unique valine gatekeeper mutants of IP6K1 and IP6K2, compared to the respective wild-type kinases. Biochemical validation experiments revealed an allosteric mechanism of action that was corroborated by HDX-MS measurements. The latter analysis suggested that displacement of the 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 wild-type kinases.

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Aguirre, T., Hostachy, S., Dornan, G. L., Neuenschwander, M., Seyffarth, C., Haucke, V., Schuetz, A., von Kries, J. P., Fiedler, D.. 2023-04-26. An unconventional gatekeeper mutation sensitizes inositol hexakisphosphate kinases to an allosteric inhibitor. https://doi.org/10.1101/2023.04.26.538378

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