RAS–Phosphoinositide 3-kinase alpha protein–protein interface (RAS–PI3Kα PPI)

The RAS–Phosphoinositide 3-kinase alpha (PI3Kα) protein–protein interface is a fundamental regulatory junction in cellular signaling, where active RAS GTPases bind directly to the Ras-binding domain (RBD) of the p110α catalytic subunit of PI3Kα (Gupta et al., 2007). This interaction is a prerequisite for the recruitment of PI3Kα to the plasma membrane and its subsequent activation, which triggers the AKT/mTOR signaling cascade to promote cell growth, survival, and metabolism (Castellano & Downward, 2011). In many human cancers, particularly those involving KRAS or PIK3CA mutations, this interface is constitutively active or hyper-responsive, driving uncontrolled tumor progression (Fritsch et al., 2013). Unlike traditional ATP-competitive kinase inhibitors that target the catalytic site, therapeutic strategies targeting this interface aim to disrupt the physical association between RAS and PI3Kα. This approach is hypothesized to provide greater selectivity for RAS-driven signaling and potentially reduce the systemic toxicities, such as severe hyperglycemia, often associated with pan-PI3K or catalytic p110α inhibition (Molina-Arcas et al., 2013). While no drugs targeting this specific interface are currently FDA-approved, research into small molecules and peptidomimetics that can disrupt this protein-protein interaction remains a high-priority frontier in precision oncology (He et al., 2021).

Other names

RAS-p110α interfaceRAS-PI3K interaction siteRAS-RBD complexRAS-PIK3CA interface

Disruption of the physical interaction between RAS GTPases and the Ras-binding domain (RBD) of the p110α subunit of PI3K, preventing membrane recruitment and subsequent RAS-mediated activation of the PI3K/AKT signaling pathway.