Publications

• Phosphatidate phosphohydrolase catalyzes the hydrolysis of ceramide 1-phosphate, lysophosphatidate, and sphingosine 1-phosphate.

  Waggoner D.W., Gomez-Munoz A., Dewald J., Brindley D.N.

  A Mg2+-independent phosphatidate phosphohydrolase was purified from rat liver plasma membranes in two distinct forms, an anionic protein and a cationic protein. Both forms of the enzyme dephosphorylated phosphatidate, ceramide 1-phosphate, lysophosphatidate, and sphingosine 1-phosphate. When assay ... >> More

  A Mg2+-independent phosphatidate phosphohydrolase was purified from rat liver plasma membranes in two distinct forms, an anionic protein and a cationic protein. Both forms of the enzyme dephosphorylated phosphatidate, ceramide 1-phosphate, lysophosphatidate, and sphingosine 1-phosphate. When assayed at a constant molar ratio of lipid to Triton X-100 of 1:500, the apparent Km values of the anionic phosphohydrolase for the lipid substrates was 3.5, 1.9, 0.4, and 4.0 microM, respectively. The relative catalytic efficiency of the enzyme for phosphatidate, ceramide 1-phosphate, lysophosphatidate, and sphingosine 1-phosphate was 0.16, 0.14, 0.48, and 0.04 liter (min x mg)-1, respectively. The hydrolysis of phosphatidate was inhibited competitively by ceramide 1-phosphate, lysophosphatidate, and sphingosine 1-phosphate. The Ki(app) values were 5.5, 5.9, and 4.0 microM, respectively. The hydrolysis of phosphatidate by the phosphohydrolase conformed to a surface dilution kinetic model. It is concluded that the enzyme is a lipid phosphomonoesterase that could modify the balance of phosphatidate, ceramide 1-phosphate, lysophosphatidate, and sphingosine 1-phosphate relative to diacylglycerol, ceramide, monoacylglycerol, and sphingosine, respectively. The enzyme could thus play an important role in regulating cell activation and signal transduction. << Less

  J. Biol. Chem. 271:16506-16509(1996) [PubMed] [EuropePMC]

• Lipid phosphate phosphohydrolase-1 degrades exogenous glycerolipid and sphingolipid phosphate esters.

  Jasinska R., Zhang Q.-X., Pilquil C., Singh I., Xu J., Dewald J., Dillon D.A., Berthiaume L.G., Carman G.M., Waggoner D.W., Brindley D.N.

  Lipid phosphate phosphohydrolase (LPP)-1 cDNA was cloned from a rat liver cDNA library. It codes for a 32-kDa protein that shares 87 and 82% amino acid sequence identities with putative products of murine and human LPP-1 cDNAs, respectively. Membrane fractions of rat2 fibroblasts that stably expre ... >> More

  Lipid phosphate phosphohydrolase (LPP)-1 cDNA was cloned from a rat liver cDNA library. It codes for a 32-kDa protein that shares 87 and 82% amino acid sequence identities with putative products of murine and human LPP-1 cDNAs, respectively. Membrane fractions of rat2 fibroblasts that stably expressed mouse or rat LPP-1 exhibited 3.1-3. 6-fold higher specific activities for phosphatidate dephosphorylation compared with vector controls. Increases in the dephosphorylation of lysophosphatidate, ceramide 1-phosphate, sphingosine 1-phosphate and diacylglycerol pyrophosphate were similar to those for phosphatidate. Rat2 fibroblasts expressing mouse LPP-1 cDNA showed 1.6-2.3-fold increases in the hydrolysis of exogenous lysophosphatidate, phosphatidate and ceramide 1-phosphate compared with vector control cells. Recombinant LPP-1 was located partially in plasma membranes with its C-terminus on the cytosolic surface. Lysophosphatidate dephosphorylation was inhibited by extracellular Ca2+ and this inhibition was diminished by extracellular Mg2+. Changing intracellular Ca2+ concentrations did not alter exogenous lysophosphatidate dephosphorylation significantly. Permeabilized fibroblasts showed relatively little latency for the dephosphorylation of exogenous lysophosphatidate. LPP-1 expression decreased the activation of mitogen-activated protein kinase and DNA synthesis by exogenous lysophosphatidate. The product of LPP-1 cDNA is concluded to act partly to degrade exogenous lysophosphatidate and thereby regulate its effects on cell signalling. << Less

  Biochem. J. 340:677-686(1999) [PubMed] [EuropePMC]

  This publication is cited by 8 other entries.

• Cloning and characterization of two human isozymes of Mg2+-independent phosphatidic acid phosphatase.

  Kai M., Wada I., Imai S., Sakane F., Kanoh H.

  We obtained two human cDNA clones encoding phosphatidic acid phosphatase (PAP) isozymes named PAP-2a (Mr = 32,158) and -2b (Mr = 35, 119), both of which contained six putative transmembrane domains. Both enzymes were glycosylated and cleaved by N-glycanase and endo-beta-galactosidase, thus suggest ... >> More

  We obtained two human cDNA clones encoding phosphatidic acid phosphatase (PAP) isozymes named PAP-2a (Mr = 32,158) and -2b (Mr = 35, 119), both of which contained six putative transmembrane domains. Both enzymes were glycosylated and cleaved by N-glycanase and endo-beta-galactosidase, thus suggesting their post-Golgi localization. PAP-2a and -2b shared 47% identical sequence and were judged to be the human counterparts of the previously sequenced mouse 35-kDa PAP(83% identity) and rat Dri42 protein (94% identity), respectively. Furthermore, the sequences of both PAPs were 34-39% identical to that of Drosophila Wunen protein. In view of the functions ascribed to Wunen and Dri42 in germ cell migration and epithelial differentiation, respectively, these findings unexpectedly suggest critical roles of PAP isoforms in cell growth and differentiation. Although the two PAPs hydrolyzed lysophosphatidate and ceramide-1-phosphate in addition to phosphatidate, the hydrolysis of sphingosine-1-phosphate was detected only for PAP-2b. PAP-2b was expressed almost ubiquitously in all human tissues examined, whereas the expression of PAP-2a was relatively variable, being extremely low in the placenta and thymus. In HeLa cells, the transcription of PAP-2a was not affected by different stimuli, whereas PAP-2b was induced (up to 3-fold) by epidermal growth factor. These findings indicate that despite structural similarities, the two PAP isozymes may play distinct functions through their different patterns of substrate utilization and transcriptional regulation. << Less

  J. Biol. Chem. 272:24572-24578(1997) [PubMed] [EuropePMC]

  This publication is cited by 5 other entries.