Characterization of the membrane interactions of phospholipase Cgamma reveals key features of the active enzyme

Citation:

Le Huray KIP, Bunney TD, Pinotsis N, Kalli AC, Katan M. Characterization of the membrane interactions of phospholipase Cgamma reveals key features of the active enzyme. Sci AdvSci Adv. 2022;8:eabp9688.

Abstract:

PLCgamma enzymes are autoinhibited in resting cells and form key components of intracellular signaling that are also linked to disease development. Insights into physiological and aberrant activation of PLCgamma require understanding of an active, membrane-bound form, which can hydrolyze inositol-lipid substrates. Here, we demonstrate that PLCgamma1 cannot bind membranes unless the autoinhibition is disrupted. Through extensive molecular dynamics simulations and experimental evidence, we characterize membrane binding by the catalytic core domains and reveal previously unknown sites of lipid interaction. The identified sites act in synergy, overlap with autoinhibitory interfaces, and are shown to be critical for the phospholipase activity in cells. This work provides direct evidence that PLCgamma1 is inhibited through obstruction of its membrane-binding surfaces by the regulatory region and that activation must shift PLCgamma1 to a conformation competent for membrane binding. Knowledge of the critical sites of membrane interaction extends the mechanistic framework for activation, dysregulation, and therapeutic intervention.

Notes:

Le Huray, Kyle I PBunney, Tom DPinotsis, NikosKalli, Antreas CKatan, MatildaengMC_PC_MR/T032774/1/MRC_/Medical Research Council/United KingdomMR/P028160/1/MRC_/Medical Research Council/United KingdomSci Adv. 2022 Jun 24;8(25):eabp9688. doi: 10.1126/sciadv.abp9688. Epub 2022 Jun 24.

Contact Details

Biochemistry, Chemistry Department
National and Kapodistrian University of Athens
(+30) 210-727 4493
Zografou
Athens, ZipCode 157 84

Recent Publications

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Gong GQ, Bilanges B, Allsop B, Masson GR, Roberton V, Askwith T, Oxenford S, Madsen RR, Conduit SE, Bellini D, et al. A small-molecule PI3Kalpha activator for cardioprotection and neuroregeneration. Nature. 2023;618:159-168.Abstract

Harnessing the potential beneficial effects of kinase signalling through the generation of direct kinase activators remains an underexplored area of drug development(1-5). This also applies to the PI3K signalling pathway, which has been extensively targeted by inhibitors for conditions with PI3K overactivation, such as cancer and immune dysregulation. Here we report the discovery of UCL-TRO-1938 (referred to as 1938 hereon), a small-molecule activator of the PI3Kalpha isoform, a crucial effector of growth factor signalling. 1938 allosterically activates PI3Kalpha through a distinct mechanism by enhancing multiple steps of the PI3Kalpha catalytic cycle and causes both local and global conformational changes in the PI3Kalpha structure. This compound is selective for PI3Kalpha over other PI3K isoforms and multiple protein and lipid kinases. It transiently activates PI3K signalling in all rodent and human cells tested, resulting in cellular responses such as proliferation and neurite outgrowth. In rodent models, acute treatment with 1938 provides cardioprotection from ischaemia-reperfusion injury and, after local administration, enhances nerve regeneration following nerve crush. This study identifies a chemical tool to directly probe the PI3Kalpha signalling pathway and a new approach to modulate PI3K activity, widening the therapeutic potential of targeting these enzymes through short-term activation for tissue protection and regeneration. Our findings illustrate the potential of activating kinases for therapeutic benefit, a currently largely untapped area of drug development.

Nikos Pinotsis

Associate Professor, Chemistry