Phosphoinositide 3-kinase–protein kinase B–mammalian target of rapamycin signaling pathway (PI3K–Akt–mTOR pathway (also written as PI3K/AKT/mTOR pathway))

The Phosphoinositide 3-kinase–protein kinase B–mammalian target of rapamycin pathway is a conserved intracellular signal transduction pathway controlling cell survival, growth, metabolism, proliferation, and resistance to apoptosis in response to growth factors and metabolic cues. It is initiated by PI3K activation at the cell membrane, which generates lipid messengers that recruit and activate Akt (protein kinase B). Akt then phosphorylates various protein targets, regulating survival and proliferation, and activates mTOR (mammalian target of rapamycin), which further promotes growth, protein synthesis, and metabolism. Dysregulation and hyperactivation of this pathway are implicated in many cancers and confer resistance to conventional therapies. Drugs targeting PI3K, Akt, or mTOR (alone or in combination) are approved or in development for treating cancer but have significant toxicity and resistance challenges. Biomarker-driven approaches, especially identification of PIK3CA mutations or PTEN loss, are increasingly used to select patients most likely to benefit from these inhibitors. Note: The query refers to an entire pathway, not a unique molecular target. For structured databases, one should extract information on each core component (PI3K, Akt, mTOR) for drug development or biological annotation purposes, rather than using the pathway as a single "receptor" or "target".

Other names

PI3K–Akt–mTOR pathwayPI3K/AKT pathwayAKT pathwaymTOR pathwayPI3K pathway

Inhibition of lipid kinase activity (PI3K inhibitors block PIP3 production, limiting downstream Akt activation) Inhibition of serine/threonine kinase activity (Akt and mTOR inhibitors block phosphorylation of effector proteins necessary for survival, proliferation, and translation) Combined inhibition interrupts feedback loops and compensatory survival pathways in tumor cells