PI3K: The Lipid Kinase Component

PI3K represents a family of lipid kinases that modify membrane phosphoinositides.

Following activation, PI3K can phosphorylate phosphatidylinositol-4,5-bisphosphate (PIP2) to generate:

Phosphatidylinositol-3,4,5-trisphosphate (PIP3)

PIP3 acts as an important signaling lipid at the inner surface of the plasma membrane.

Its production creates a localized molecular platform that facilitates the recruitment of proteins containing pleckstrin homology (PH) domains, including AKT.

The generation and removal of PIP3 are therefore important regulatory steps in controlling pathway activity.