Structural and allosteric effects of the membrane-bound PI3Kα H1047R mutation and opportunities for drug discovery.

PI3Kα is a lipid kinase that regulates cell growth and survival via the PI3Kα/Akt pathway. As a peripheral membrane protein, PI3Kα is activated at the membrane, however, its active conformation remains unknown. To investigate how PI3Kα and its most prevalent oncogenic mutation, H1047R, interact with the membrane, we performed Molecular Dynamics simulations of active-like PI3Kα WT and H1047R mutant in complex with HRAS on a model membrane. Our simulations reveal that the H1047R mutation enhances substrate coordination, promotes catalytic interactions, and induces an open C-terminal conformation that stabilizes the protein on the membrane. Moreover, H1047R strengthens allosteric coupling between the C-terminus and membrane-binding loop 2 in both solution and membrane-bound states. WT and mutant proteins adopt distinct conformational ensembles on the membrane, enabling structure-based prediction of allosteric pockets at the protein-membrane interface. These findings offer a mechanistic basis for the H1047R enhanced membrane-binding ability and insights for new therapeutic strategies targeting the protein-membrane interface.