Gramzow M, Schröder H C, Fritsche U, Kurelec B, Robitzki A, Zimmermann H, Friese K, Kreuter M H, Müller W E
Institut für Physiologische Chemie, Universität, Mainz Federal Republic of Germany.
Cell. 1989 Dec 1;59(5):939-48. doi: 10.1016/0092-8674(89)90616-8.
Using the Geodia cydonium system, we showed that after incubation of competent sponge cells in the presence of lectin, phospholipase A2 was released from the cells. The substrates for this enzyme, phosphatidylethanolamine and phosphatidylcholine, were identified in the extracellular material of sponge tissue. In addition, the phospholipase A2 inhibitor calelectrin was identified by immunobiochemical techniques; this molecule was associated with the aggregation factor. Reconstitution experiments strongly suggested that phospholipase A2 catalyzed the release of arachidonic acid, which is then taken up by the cells. Intracellularly, arachidonic acid was metabolized primarily to prostaglandin E2. Inhibition studies revealed that prostaglandin E2 is involved in the ultimate increase of DNA synthesis. These findings suggest that the phospholipase A2-arachidonic acid system is involved in the matrix-initiated signal transduction pathway in sponges.
使用乔氏地海绵（Geodia cydonium）系统，我们发现，在凝集素存在的情况下孵育感受态海绵细胞后，磷脂酶A2从细胞中释放出来。该酶的底物磷脂酰乙醇胺和磷脂酰胆碱在海绵组织的细胞外物质中被鉴定出来。此外，通过免疫生化技术鉴定出磷脂酶A2抑制剂钙电蛋白；该分子与聚集因子相关。重组实验有力地表明，磷脂酶A2催化花生四烯酸的释放，然后花生四烯酸被细胞摄取。在细胞内，花生四烯酸主要代谢为前列腺素E2。抑制研究表明，前列腺素E2参与了DNA合成的最终增加。这些发现表明，磷脂酶A2 - 花生四烯酸系统参与了海绵中基质引发的信号转导途径。
