Phosphatidylinositol 4-phosphate (PtdIns4P, PI-4-P or simply PI4P) is a precursor of Phosphatidylinositol (4,5)-bisphosphate. PtdIns4P is prevalent in the membrane of the Golgi apparatus.
In the Golgi apparatus, PtdIns4P binds to the GTP-binding protein ARF and to effector proteins, including four-phosphate-adaptor protein 1 and 2 (FAPP1 and FAPP2). This three molecule complex recruits proteins that need to be carried to the cell membrane.
There is now evidence that PI-4-P is capable of deforming lipid systems into tightly curved assemblies, this is consistent with similar behaviour observed in phosphatidylinositol.
- ^ Godi A et al., FAPPs control Golgi-to-cell-surface membrane traffic by binding to ARF and PtdIns(4)P. Nat Cell Biol. 2004 May;6(5):393-404.
- ^ Choudhury RR, Hyvola N, Lowe M. Phosphoinositides and membrane traffic at the trans-Golgi network. Biochem Soc Symp. 2005;(72):31-8.
- ^ Furse, Samuel; Brooks, Nicholas J.; Seddon, Annela M.; Woscholski, Rüdiger; Templer, Richard H.; Gaffney, Piers R. J.; Ces, Oscar (2012). "Lipid Membrane Curvature Induced by Distearoyl Phosphatidylinositol 4-Phosphate". Soft Matter 8: 3090–3093. doi:10.1039/c2sm07358g.