Rotation of the N-terminal helix triggers Gα activation.
Heterotrimeric G proteins, activated by G-protein-coupled receptors (GPCRs), are central mediators of cellular signaling. Activation requires GDP release from the Gα subunit, a step attributed largely to the C-terminal α5 helix, the primary GPCR-interacting region. Contributions from other Gα regions have remained uncl...