General structure

Chemical structure of sn-1-stearoyl-2-arachidonoyl phosphatidylinositol (3,4)-bisphosphate

Phosphatidylinositol (3,4)-bisphosphate (PtdIns(3,4)P₂) is a minor phospholipid component of cell membranes, yet an important second messenger. The generation of PtdIns(3,4)P₂ at the plasma membrane activates a number of important cell signaling pathways.

PtdIns(3,4)P₂ is dephophosphorylated by the phosphatase PTEN on the 3 position of the inositol ring and by the TPTE (transmembrane phosphatases with tensin homology) family of phosphatases on the 4 position of the inositol ring.

The PH domain in a number of proteins binds to PtdIns(3,4)P₂ including the PH domain in PKB. The generation of PtdIns(3,4)P₂ at the plasma membrane upon the activation of class I PI 3-kinases and SHIP phosphatases causes these proteins to translocate to the plasma membrane, thereby effecting their activity.

de:Phosphatidylinositol-4,5-bisphosphat es:Fosfatidilinositol 3,4-bifosfato

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