Phosphoinositide 3-kinase

Phosphoinositide -3- kinases ( PI3-kinase, PI3K ) are enzymes whose activity is to be found in all eukaryotic cells. They play an important role in signal transduction and are involved in a variety of key cellular functions such as cell growth, cell proliferation, migration, differentiation, survival and cell adhesion involved. In humans, changes in the structure, activity or regulation of PI3K to diseases, such as allergies, inflammation, heart disease and cancer can result.

PI3K catalyzes the phosphorylation of the 3'-OH position of the inositol ring of certain phospholipids in the cell membrane, the so-called phosphatidylinositols. These phosphoinositides, in particular phosphatidylinositol -3 ,4,5- trisphosphate ( PIP3 ), serve as docking sites for other proteins, such as protein kinase B (also known as Akt) and PDK1. The most important pathway, the PI3K is activated the PI3K/Akt signaling pathway. An opponent of PI3K is the phosphatase PTEN is an important tumor suppressor.

The PI3- kinase superfamily consists of several structurally related enzymes that are divided into three functional classes IA, IB, II and III according to the protein domain structure of the catalytic subunits and consist of a total of eight isoforms:

• Phosphorylation of phosphatidylinositol ( PtdIns ), PtdIns4P and PtdIns (4,5) P2 (preferred): Class IA PI3K ( EC 2.7.1.153 ): p110α, p110β, p110δ
• Class IB PI3K: p110γ

• Class II PI3K ( EC 2.7.1.154 ): PI3K - C2α, PI3K - C2β, PI3K C2γ

• Class III PI3K ( EC 2.7.1.137 ): VPS34

An example of a PI3K inhibitor wortmannin.

The PI -3 kinase was discovered in 1985 by Lewis C. Cantley and colleagues.