The DIPP1 family binds IP8 in catalytically-productive twist-boat and chair conformations and associates in a ligand-dependent manner.

Casas-Florez D., Whitfield H., Pérez-Cañadillas JM., Monterroso B., Riley AM., Márquez-Moñino MA., Shipton ML., Sanz-Aparicio J., Brearley CA., Potter BVL., González B.

Diphosphoinositol Polyphosphate Phosphohydrolase 1 (DIPP1) is a Nudix hydrolase involved in inositol pyrophosphate (PP-InsP) metabolism, critical for cellular signaling, energy homeostasis, and stress responses. We report crystallographic and computational studies that reveal 1,5-bis-diphosphoinositol tetrakisphosphate (IP8) binds to DIPP1 in two catalytically-productive inositol ring conformations. IP8 hydrolysis at the 1-position requires a twist-boat conformation, whereas at the 5-position a canonical chair conformation is adopted. Additionally, structural and biophysical characterization shows that the DIPP1 family undergoes ligand-sensitive changes in the association state that might be further modulated by salt concentration and/or phosphate ions. Taken together, these results advance our understanding of DIPP1 in the dynamic regulation of inositol pyrophosphate signaling networks. They provide a detailed view of DIPP1 substrate recognition and suggest oligomerization as a novel regulatory mechanism, with broader implications for phosphate sensing and functional protein-protein interactions.

DOI

10.1016/j.ijbiomac.2026.152715

Type

Journal article

Publication Date

2026-05-26T00:00:00+00:00

Keywords

DIPP1, IP(8), Inositol polyphosphate, Nudix hydrolase, Twist-boat, inositol pyrophosphate

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