Phosphatidylinositol 3-phosphate (PI3P) is a phospholipid found in cell membranes that helps to recruit a range of proteins, many of which are involved in protein trafficking, to the membranes. It is the product of both the class II and III phosphoinositide 3-kinases (PI 3-kinases) activity on phosphatidylinositol.[1]
 | |
| Names | |
|---|---|
| Other names sn-1-stearoyl-2-arachidonoyl phosphatidylinositol 3-phosphate | |
| Identifiers | |
| Abbreviations | PtdIns3P PtdIns(3)P PI3P PI(3)P |
PubChem CID | |
CompTox Dashboard (EPA) | |
| Properties | |
| C11H20O16P2 | |
| Molar mass | 470.214 g/mol, neutral with fatty acid composition - 18:0, 20:4 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
PtdIns3P is dephosphorylated by the myotubularin family of phosphatases, on the D3 position of the inositol ring, and can be converted to PtdIns(3,5)P2 by the lipid kinase PIKfyve.[2]
Both FYVE domains and PX domains – found in proteins such as SNX1, HGS, and EEA1 – bind to PtdIns3P.[3]
The majority of PtdIns3P appears to be constitutively synthesised by the class III PI 3-kinase, PIK3C3 (Vps34), at endocytic membranes. Class II PI 3-kinases also appear to synthesise PtdIns3P, their activity however appears to be regulated by a range of stimuli, including growth factors. This suggests that specific pools of PtdIns3P may be synthesised upon cell stimulation.