Cyclic Phosphatidic Acid Is Produced by Autotaxin in Blood

Abstract

Cyclic phosphatidic acid (cPA), an analog of lysophosphatidic acid (LPA), was previously identified in human serum. Although cPA possesses distinct physiological activities not elicited by LPA, its biochemical origins have scarcely been studied. In the present study, we assayed cPA formation from lysophosphatidylcholine in fetal bovine serum and found significant activity of transphosphatidylation that generated cPA. The cPA-producing enzyme was purified from fetal bovine serum using five chromatographic steps yielding a 100-kDa protein with cPA biosynthetic activity. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of its tryptic peptides revealed that the enzyme shared identical fragments with human autotaxin, a serum lysophospholipase D that produces LPA. Western blot analysis demonstrated that the 100-kDa protein was specifically recognized by an anti-human autotaxin antibody. Moreover, recombinant rat autotaxin was found to generate cPA in addition to LPA. No significant cPA-or LPA-producing activity was detected in autotaxin-depleted serum from bovine or human prepared by immunoprecipitation with an anti-autotaxin monoclonal antibody. These results indicate that the generation of cPA and LPA in serum is mainly attributed to autotaxin.

Cellular function and molecular structure of ecto-nucleotidases

“…NPP2 is regulated through product inhibition by both lysophosphatidic acid and S1P [381]. More recent evidence suggests that NPP2 can in addition form cyclic phosphatidic acid, an analogue of lysophosphatidic acid in which a ring closure is formed by phosphate [382]. This enters yet another dimension to the biological functions of this protein.…”

Inhibition of transcellular tumor cell migration and metastasis by novel carba-derivatives of cyclic phosphatidic acid

“…Because the 2,3-cyclic phosphate ring can be hydrolyzed by phosphodiesterases and phospholipases [20][21][22], that lead to LPA formation, we designed carba-derivatives to prevent ring opening of cPA. We demonstrate that the ccPA derivatives exert potent inhibitory effect on serum-and LPAinduced transcellular migration of MM1 cancer cells (Figs.…”

Autotaxin Regulates Vascular Development via Multiple Lysophosphatidic Acid (LPA) Receptors in Zebrafish

“…1, E and F. The catalytic activity of zebrafish ATX against physiological substrates was determined as described previously (24). Briefly, ATX-depleted mouse plasma was prepared using anti-mouse ATX monoclonal antibodies coupled to Sepharose 4B as described (25) and incubated with recombinant zATX (10 g/ml) at 37°C for 6 h. Production of various LPA species during the incubation was determined by LC-MS/MS as described previously (24).…”