PPAPDC2 is a phosphatase that dephosphorylates Presqualene diphosphate (PSDP) into presqualene monophosphate (PSMP), suggesting that it may have important role in innate immunity. PSDP is a bioactive lipid that rapidly remodels to PSMP upon cell activation. PPAPDC2 displays diphosphate phosphatase activity with a substrate preference for PSDP > FDP > phosphatidic acid. PPAPDC2 activity is independent of Mg2+ and has been identified in activated human neutrophil (PMN) extracts. It is widely expressed in human tissues. Recent studies shows PPAPDC2 is a functional isoprenoid diphosphate phosphatase.