Biology subjects

Dornan, G. L.

Publications and source records attributed to Dornan, G. L..

2 recordsLinked to original sources

bioRxiv2023

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

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.

biochemistry↗

bioRxiv2019

Defining how oncogenic and developmental mutations of PIK3R1 alter the regulation of class IA phosphoinositide 3-kinases

The class IA PI3Ks are key signalling enzymes composed of a heterodimer of a p110 catalytic subunit and a p85 regulatory subunit, with PI3K mutations being causative of multiple human diseases including cancer, primary immunodeficiencies, and developmental disorders. Mutations in the p85 regulatory subunit encoded by PIK3R1 can both activate PI3K through oncogenic truncations in the iSH2 domain, or inhibit PI3K through developmental disorder mutations in the cSH2 domain. Using a combined biochemical and hydrogen deuterium exchange mass spectrometry approach we have defined the molecular basis for how these mutations activate both the p110/p110{delta} catalytic subunits. We find that the oncogenic Q572* truncation of PIK3R1 disrupts all inhibitory inputs, with p110 being hyper-activated compared to p110{delta}. In addition, we find that the R649W mutation in the cSH2 of PIK3R1 decreases sensitivity to activation by receptor tyrosine kinases. This work reveals novel insight into isoform specific regulation of p110s by p85.\n\nHighlights- An oncogenic variant of p85, Q572*, leads to hyper-activation of p110 compared to p110{delta}\n- HDX-MS revealed that Q572* leads to disruption of all inhibitory interfaces in p110\n- A SHORT syndrome mutation in p85 leads to decreased sensitivity to RTKs for p110/{delta}

biochemistry↗