Phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P2) is one of the seven phosphoinositides found in eukaryotic cell membranes.[1]
In quiescent cells, the PtdIns(3,5)P2 levels, typically quantified by HPLC, are the lowest amongst the constitutively present phosphoinositides. They are approximately 3 to 5-fold lower as compared to PtdIns3P and PtdIns5P (Phosphatidylinositol 5-phosphate) levels, and more than 100-fold lower than the abundant PtdIns4P (Phosphatidylinositol 4-phosphate) and PtdIns(4,5)P2.[2]
PtdIns(3,5)P2 was first reported to occur in mouse fibroblasts and budding yeast S. cerevisiae in 1997.[3][4]
In S. cerevisiae PtdIns(3,5)P2 levels increase dramatically during hyperosmotic shock.[4]
The response to hyperosmotic challenge is not conserved in most tested mammalian cells except for differentiated 3T3L1 adipocytes.
[4][5]
^Di Paolo G, De Camilli P. Phosphoinositides in cell regulation and membrane dynamics. Nature. 2006 Oct 12;443(7112):651-7. PMID17035995
^Shisheva A. Regulating Glut4 vesicle dynamics by phosphoinositide kinases and phosphoinositide phosphatases. Front Biosci. 2003 Sep 1;8:s945-56. Review. PMID12957825
^Whiteford CC, Brearley CA, Ulug ET. Phosphatidylinositol 3,5-bisphosphate defines a novel PI 3-kinase pathway in resting mouse fibroblasts. Biochem J. 1997 May 1;323 ( Pt 3):597-601. PMID9169590
^Sbrissa D, Shisheva A. Acquisition of unprecedented phosphatidylinositol 3,5-bisphosphate rise in hyperosmotically stressed 3T3-L1 adipocytes, mediated by ArPIKfyve-PIKfyve pathway. J Biol Chem. 2005 Mar 4;280(9):7883-9. Epub 2004 Nov 16. PMID15546865