Mammalian lipid phosphate phosphohydrolases

Abstract

We are at an exciting point where various LPP isoforms have been identified. The regulation of LPP homologs has not been investigated in detail. Another area of uncertainty is the full extent of the LPP family and whether other LPPs exist with relatively little sequence homology. The exact subcellular localization for each mammalian LPP is not yet known. Therefore, we do not know the extent to which different lipid phosphates have access to the LPP isoforms. The identification of lyso-PA and S-1-P as physiological extracellular messengers and our observations that LPPs can dephosphorylate these exogenous substrates imply a role for the LPPs in modulating extracellular signaling. Equally we need to understand the roles of the LPP isoforms in dephosphorylating intracellular signals from lipid phosphates. These studies can now be undertaken to elucidate the functions of each LPP isoform in regulating signal transduction.