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

The RAS–PI3Kα interface is a pivotal protein-protein interaction (PPI) that links the RAS small GTPases (KRAS, HRAS, and NRAS) to the phosphoinositide 3-kinase (PI3K) signaling pathway. This interaction occurs when active, GTP-bound RAS binds to the Ras-binding domain (RBD) of the p110α catalytic subunit of PI3Kα, leading to the production of PIP3 and subsequent activation of the AKT/mTOR survival pathway (Castellano & Downward, 2011). In many human malignancies, such as pancreatic and lung cancers, oncogenic mutations in RAS lead to hyperactivation of this interface, making it a high-priority therapeutic target (Fritsch et al., 2013). Disrupting this specific interface aims to decouple RAS from one of its most potent downstream effectors without necessarily inhibiting the basal activity of PI3K or other RAS effectors like RAF. Small molecules such as rigosertib have been characterized as RAS mimetics that occupy the RBD of effectors, thereby blocking the RAS-PI3K association (Athuluri-Divakar et al., 2016). While promising, targeting this interface faces challenges including the high affinity of the natural interaction and potential systemic side effects like hyperglycemia, which is common with PI3K pathway modulation. Current research focuses on developing highly selective inhibitors that can disrupt this interaction in mutant RAS contexts while sparing normal cellular signaling.

Other names

RAS-PI3K interactionp110α-RAS interfaceRAS-binding domain of PI3KαKRAS-PI3Kα complexRAS-PI3Kα protein-protein interaction

Disruption of the physical interaction between active, GTP-bound RAS isoforms and the Ras-binding domain (RBD) of the PI3Kα catalytic subunit (p110α), thereby preventing RAS-mediated activation of the PI3K/AKT/mTOR signaling pathway (Athuluri-Divakar et al., 2016).