Phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha:RAS protein-protein interaction (PI3Kalpha:RAS PPI)

The Phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha (PI3Kalpha) RAS-binding domain (RBD) mediates the critical protein-protein interaction (PPI) between PI3Kalpha and activated RAS GTPases (Gupta et al., 2007, Cell). This interaction is a fundamental mechanism for the recruitment of PI3K to the plasma membrane, where it catalyzes the production of the second messenger phosphatidylinositol 3,4,5-trisphosphate (PIP3), subsequently activating the AKT/mTOR signaling pathway (Castellano & Downward, 2011, Genes & Cancer). In many cancers, particularly those driven by KRAS mutations, this interaction is essential for tumor initiation and maintenance, as demonstrated in mouse models where loss of the PI3K-RAS interaction prevents lung tumor formation (Gupta et al., 2007, Cell). While traditional PI3K inhibitors target the ATP-binding catalytic site, targeting the PI3Kalpha:RAS PPI offers a strategy to specifically block RAS-dependent PI3K signaling (Athuluri-Divakar et al., 2016, Cell). This approach aims to potentially reduce the systemic toxicities, such as hyperglycemia, often associated with broad catalytic inhibition of PI3Kalpha by sparing RAS-independent PI3K functions. Current therapeutic development focuses on small molecules like Rigosertib and various peptidomimetics that can sterically hinder the binding interface between the RBD and RAS (Workman et al., 2014, Cancer Discovery).

Other names

p110alpha:RAS interactionPIK3CA:RAS interactionPI3K-RAS binding interfacePI3Kalpha-RAS protein-protein interaction

Disruption of the physical interaction between the RAS-binding domain (RBD) of PI3Kalpha and activated RAS GTPases, preventing the recruitment and activation of PI3K at the plasma membrane.