Integrative computational simulations uncover the conformational activation pathway of AKT1 kinase.

The AKT1 kinase, a central node in the PI3K-AKT-mTOR signaling axis, governs critical cellular processes, including survival and proliferation, and its dysregulation drives cancer, diabetes, and neurodegeneration. While structural studies have resolved static snapshots of AKT1's inactive and active states, the dynamic mechanisms orchestrating its activation, particularly the coupling of phosphorylation-induced signals to catalytic competency, remain poorly resolved. This knowledge gap hinders the development of targeted therapies addressing AKT1's pathological hyperactivation. Using integrative computational approaches, we characterize the hierarchical conformational transitions enabling AKT1 activation at atomic resolution. Microsecond-scale molecular dynamics (MD) simulations and nudged elastic band (NEB) pathway analyses reveal that phosphorylation at T308 initiates a metastable "pre-active" state, destabilizing autoinhibitory interactions at the PH-kinase interface. This triggers potential structural rearrangements: (1) A-loop opening exposes the hydrophobic motif for regulatory phosphorylation, (2) αC-helix rotation establishes the Lys179-Glu198 catalytic salt bridge, and (3) DFG motif flipping enables Asp292-Mg2+ coordination, completing the active site assembly. By mapping the energy landscape of AKT1 activation, this work bridges static structural data with dynamic mechanistic insights, offering a framework for therapeutic intervention against AKT1-driven pathologies.