PtdIns-(3,5)-P2 (1,2-dipalmitoyl) (sodium salt) is a synthetic analog of natural PtdIns featuring saturated C16:0 fatty acids at the sn-1 and sn-2 positions. The compound features the same inositol and DAG stereochemistry as that of the natural compound. PtdIns-(3,5)-P2 is rapidly synthesized from PtdIns-(3)-P1 in yeast when a PtdIns-(3)-P5-OH kinase is activated during hyperosmotic conditions. PtdIns-(3,5)-P2 is also present in mammalian cells, such as monkey COS-7 cells, where a similar biosynthetic route has been demonstrated.