| First Author | Morioka Y | Year | 2000 |
| Journal | Arch Biochem Biophys | Volume | 381 |
| Issue | 1 | Pages | 31-42 |
| PubMed ID | 11019817 | Mgi Jnum | J:64346 |
| Mgi Id | MGI:1889123 | Doi | 10.1006/abbi.2000.1977 |
| Citation | Morioka Y, et al. (2000) Mouse group X secretory phospholipase A2 induces a potent release of arachidonic acid from spleen cells and acts as a ligand for the phospholipase A2 receptor. Arch Biochem Biophys 381(1):31-42 |
| abstractText | Group X secretory phospholipase A2 (sPLA2-X) has recently been shown to possess a powerful potency for releasing arachidonic acid from cell membrane phospholipids. Here, we report the purification of mouse pro- and mature forms of sPLA2-X, as well as its expression and biological functions. Purified pro-sPLA2-X was found to possess a propeptide of 11 amino acid residues attached at the NH2-terminals of the mature protein, and showed as little as 8% of the PLA2 activity of the mature form. Limited proteolysis of pro-sPLA2-X with trypsin resulted in the appearance of the mature form with a concomitant increase in PLA2 activity, suggesting a requirement of proteolytic removal of the propeptide for the optimal activity. The expression of sPLA2-X mRNA was detected in various tissues including the lung, thymus, and spleen, and immunohistochemical analysis revealed its expression in splenic macrophages. In the spleen cells, mature sPLA2-X elicited a prompt release of arachidonic acid with significant production of prostaglandin E2 more efficiently than group IB and IIA sPLA2s. In addition, sPLA2-X was identified as a high-affinity ligand for both native and recombinant form of mouse PLA2 receptor (PLA2R). However, there was no significant difference in the sPLA2-X-induced arachidonic acid release responses in the spleen cells between wild-type and PLA2R-deficient mice. These findings strongly suggest that sPLA2-X possesses two distinct biological functions in mice: it elicits a marked release of arachidonic acid from membrane phospholipids leading to the production of lipid mediators based on its enzymatic potency, and it acts as a natural ligand for the PLA2R that has been shown to play a critical role in the production of inflammatory cytokines during endotoxic shock. |
