Phosphoinositide 3-kinases

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Phosphoinositide-3-kinases (PI3-Kinase, PI3K) are enzymes whose activity can 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 . In humans, changes in the structure, activity or regulation of the PI3K can lead to diseases such as allergies , inflammatory processes , heart diseases and cancer .

PI3K catalyzes the phosphorylation of the 3'-OH position on the inositol ring of certain phospholipids in the cell membrane , so-called phosphatidylinositols . These phosphoinositides, especially phosphatidylinositol-3,4,5-trisphosphate (PIP 3 ), serve as docking points for other proteins, such as protein kinase B (also called Akt) and PDK1 . The most important signal path that the PI3K activates is the PI3K / Akt signal path . An antagonist of PI3K is the phosphatase PTEN , which is an important tumor suppressor .

The PI3 kinase superfamily consists of several structurally related enzymes, which 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
  • Phosphorylation of PtdIns4P and PtdIns (preferred):
    • Class II-PI3K ( EC  2.7.1.154 ): PI3K-C2α, PI3K-C2β, PI3K-C2γ
  • Phosphorylation of PtdIns:

An example of a PI3K inhibitor is Wortmannin .

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

Individual evidence

  1. ↑ UniProt P42336 , UniProt P42338 , UniProt O00329
  2. ↑ UniProt P48736
  3. ↑ UniProt O00443 , UniProt O00750 , UniProt O75747
  4. ↑ UniProt Q8NEB9

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