A PHOSPHOLIPASE-D SPECIFIC FOR THE PHOSPHATIDYLINOSITOL ANCHOR OF CELL-SURFACE PROTEINS IS ABUNDANT IN PLASMA
A PHOSPHOLIPASE-D SPECIFIC FOR THE PHOSPHATIDYLINOSITOL ANCHOR OF CELL-SURFACE PROTEINS IS ABUNDANT IN PLASMA
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DOI：
10.1073/pnas.85.4.980
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发表时间：
1988-02-01
影响因子：
11.1
通讯作者：
PRASAD, ARS
中科院分区：
文献类型：
--
作者：
LOW, MG;PRASAD, ARS
先前已经报道了在许多哺乳动物组织中能够降解细胞表面蛋白的糖基-磷脂酰肌醇膜锚的酶活性。这里报道的实验表明，这种锚降解活性在哺乳动物血浆中也很丰富。EGTA或1，10-菲咯啉可抑制该酶的活性。它能够从碱性磷酸酶、5“-核苷酸酶和变体表面糖蛋白中去除锚，但对磷脂酰肌醇或磷脂酰胆碱几乎没有活性。磷脂酸是唯一的3 H-标记的产品时，这种酶水解[3 H]肉豆蔻酸标记的变体表面糖蛋白。根据其分子大小及其对1，10-菲咯啉的敏感性，可以将其与几种大鼠组织中的钙依赖性肌醇磷脂特异性磷脂酶C活性区分开来。因此，这些数据表明，这种活性是由于磷脂酶D与糖基磷脂酰肌醇结构的特异性。虽然这种锚特异性磷脂酶D的确切生理功能仍有待确定，这些研究结果表明，它可以在体内调节细胞表面蛋白的表达和释放中发挥重要作用。
An enzyme activity capable of degrading the glycosyl-phosphatidylinositol membrane anchor of cell-surface proteins has previously been reported in a number of mammalian tissues. The experiments reported here demonstrate that this anchor-degrading activity is also abundant in mammalian plasma. The activity was inhibited by EGTA or 1,10-phenanthroline. It was capable of removing the anchor from alkaline phosphatase, 5''-nucleotidase, and variant surface glycoprotein but had little or no activity toward phosphatidylinositol or phosphatidylcholine. Phosphatidic acid was the only 3H-labeled product when this enzyme hydrolyzed [3H]myristate-labeled variant surface glycoprotein. It could be distinguished from the Ca2+-dependent inositol phospholipid-specific phospholipase C activity in several rat tissues on the basis of its molecular size and its sensitivity to 1,10-phenanthroline. The data therefore suggest that this activity is due to a phospholipase D with specificity for glycosylphosphatidylinositol structures. Although the precise physiological function of this anchor-specific phospholipase D remains to be determined, these findings indicate that it could play an important role in regulating the expression and release of cell-surface proteins in vivo.