Harvey Rat Sarcoma Virus Oncogene Homolog–Phosphoinositide 3-kinase alpha interface (HRAS–PI3Kα interface) (HRAS–PI3Kα interface)

The HRAS–PI3Kα interface is a critical protein-protein interaction (PPI) site where the active, GTP-bound form of the HRAS GTPase binds to the Ras-binding domain (RBD) of the p110α catalytic subunit of Phosphoinositide 3-kinase alpha (PI3Kα). This interaction is essential for the membrane recruitment and subsequent activation of PI3Kα, which triggers the AKT/mTOR signaling cascade to promote cell growth, survival, and metabolism (UniProt P01112, P42336). In many cancers, such as head and neck squamous cell carcinoma and bladder cancer, mutations in HRAS or PIK3CA lead to hyperactivation of this pathway, driving uncontrolled tumor progression (PubMed: 29056346). Therapeutic strategies targeting this specific interface aim to disrupt the physical association between HRAS and PI3Kα, thereby selectively inhibiting oncogenic signaling while potentially sparing other RAS-mediated pathways. While broad PI3K inhibitors exist, drugs specifically targeting the HRAS–PI3Kα interface, such as RAS-mimetic small molecules like rigosertib, are being explored to improve therapeutic index and overcome resistance (PubMed: 27156451). This approach represents a shift toward precision oncology by focusing on the specific nodes of pathway crosstalk that are dysregulated in disease. Challenges in targeting this interface include the relatively flat surface of protein-protein interaction sites and the need for high specificity to avoid disrupting essential physiological RAS signaling.

Other names

HRAS-PIK3CA interfaceRAS-PI3K interfaceHRAS-p110α interaction siteHRAS-p110 alpha interface

Inhibition of the protein-protein interaction between GTP-bound HRAS and the Ras-binding domain (RBD) of the PI3Kα catalytic subunit (p110α), preventing PI3K activation and downstream AKT signaling.