HRas proto-oncogene GTPase–Phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha interface

The "HRas proto-oncogene GTPase–Phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha interface" refers to the molecular interaction surface where GTP-bound HRas contacts and activates the catalytic subunit alpha (p110α) of PI3Kα. HRas is a small GTPase that acts as a molecular switch, relaying extracellular signals to control processes like cell proliferation and survival, and is a well-known proto-oncogene whose activating mutations drive several cancers[1][3][5][7]. PI3Kα is a lipid kinase involved in the PI3K/AKT/mTOR pathway, which is also central to cancer and survival signaling. The physical interaction between active HRas and p110α enhances PI3Kα activity, although current evidence indicates that allosteric activation by receptor tyrosine kinases (RTKs) remains dominant; direct HRas binding may primarily stabilize PI3Kα at the plasma membrane and modestly increase its catalytic activity[2][4][6][8]. This interface is considered a potential anti-cancer drug target, but it is not a standalone canonical protein nor a receptor, enzyme, or transporter by itself. Rather, it represents a molecular surface of contact between two canonical drug targets. - This entity is not a standalone protein, enzyme, receptor, or transporter, but a *molecular interface* between two proteins[2][4][6]. Neither HRas nor PI3Kα should be conflated with the *interface* itself, although both are independent validated therapeutic targets. - Any drug development efforts would be directed against this dynamic protein–protein interaction, often an inherently challenging category of drug targets. For structured database or curation purposes, consider splitting this entry into its component proteins: - GTPase HRas (HRas proto-oncogene, GTPase) - Phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA/p110α)

Modulation of HRas–PI3Kα interaction can alter downstream signaling, potentially by stabilizing or disrupting protein–protein binding