Phosphatidylinositol (4,5)-bisphosphate

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Phosphatidylinositol (4,5)-bisphosphate (PtdIns(4,5)P₂) is a minor phospholipid component of cell membranes. PtdIns(4,5)P₂ is enriched at the plasma membrane where it is an important substrate for a number of important signalling proteins.^[1]

Phospholipase C hydrolyzes the phosphodiester link in PtdIns(4,5)P₂ forming inositol 1,4,5-triphosphate (InsP₃) and diacylglycerol (DAG).

PtdIns(4,5)P2₂ is formed primarily by the type I phosphatidylinositol 4 phosphate 5 kinases from PI(4)P.

Class I PI 3-kinases phosphorylate PtdIns(4,5)P₂ forming phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P₃).

PIP2 cleavage to IP3 and DAG initiates intracellular calcium release and PKC activation.

[edit] See also

• Phosphatidylinositol
• Phosphatidylinositol 3-phosphate
• Phosphatidylinositol 4-phosphate
• Phosphatidylinositol 5-phosphate
• Phosphatidylinositol (3,4)-bisphosphate
• Phosphatidylinositol (3,5)-bisphosphate
• Phosphatidylinositol (3,4,5)-trisphosphate

[edit] References

1. ^ Strachan T, Read AP (1999). Leptospira. In: Human Molecular Genetics, 2nd ed., Wiley-Liss. (via NCBI Bookshelf) ISBN 0-471-33061-2.

Lipid signaling
Phospholipase | Phosphatidylinositol (4,5)-bisphosphate | Diacylglycerol | Inositol triphosphate | Inositol triphosphate receptor