What is the Origin of PI3K-Akt Signaling?

The pathway is named after its two primary components: PI3K and Akt. The discovery of PI3K as a lipid kinase that phosphorylates inositol phospholipids, followed by the identification of Akt as a key downstream effector, established this cascade as a fundamental element of cellular signal transduction. Its significance in hormonal health became clear with the realization that the insulin receptor strongly utilizes this pathway to mediate glucose uptake.

What is the Mechanism of PI3K-Akt Signaling?

The pathway is typically activated when growth factors or hormones, such as insulin, bind to their cell surface receptors, leading to the recruitment and activation of PI3K. Activated PI3K then phosphorylates phosphatidylinositol lipids in the cell membrane, generating the secondary messenger $text{PIP}_3$. $text{PIP}_3$ recruits Akt to the membrane, where it is phosphorylated and activated by other kinases. Activated Akt then phosphorylates numerous downstream targets, which ultimately promote cell survival and, importantly, induce the translocation of glucose transporters to the cell membrane to facilitate glucose uptake.

PI3K-Akt Signaling

Meaning

PI3K-Akt signaling is a crucial intracellular pathway that regulates a vast array of cellular functions, including metabolism, cell growth, proliferation, survival, and transcription. This cascade is initiated by the enzyme Phosphatidylinositol 3-kinase (PI3K) and culminates with the activation of the protein kinase Akt, also known as Protein Kinase B (PKB). Due to its central role in cell survival and growth, dysregulation of this pathway is a hallmark of many diseases, including cancer and insulin resistance.