Phosphoinositide 3-kinase catalytic subunit (PI3K catalytic subunit (commonly p110 for class I isoforms; specific gene symbols include PIK3CA, PIK3CB, PIK3CD, PIK3CG))

The phosphoinositide 3-kinase catalytic subunits are the enzymatically active core of the PI3K enzyme family, driving the phosphorylation of phosphatidylinositols to generate key second messengers like PIP3. The most extensively studied are the class I p110 isoforms (p110α, β, δ, γ), each encoded by a distinct gene (PIK3CA, PIK3CB, PIK3CD, PIK3CG) and partnered with regulatory subunits for precise control. The PI3K pathway is essential for cell growth, survival, metabolism, and immune function, and is commonly dysregulated in cancer and immune-related diseases. These subunits represent validated drug targets, with multiple approved inhibitors, but also present substantial safety challenges due to their ubiquitous signaling roles.

Other names

PI3K p110 (with isoforms: p110α, p110β, p110δ, p110γ)Class I PI3K catalytic subunitPIK3CA, PIK3CB, PIK3CD, PIK3CGPhosphatidylinositol 3-kinase catalytic subunit

Inhibition of PI3K catalytic activity, blocking generation of phosphatidylinositol (3,4,5)-trisphosphate (PIP3), leading to reduced downstream signaling through AKT and mTOR pathways; Isoform-selective inhibition for reduced toxicity