The contact site A glycoprotein of Dictyostelium discoideum carries a phospholipid anchor of a novel type.
The contact site A glycoprotein of Dictyostelium discoideum carries a phospholipid anchor of a novel type.
复制标题
盘基网柄菌的接触位点 A 糖蛋白携带新型磷脂锚。
作者：
J. Stadler;T. W. Keenan;G. Bauer;G. Gerisch
接触位点A糖蛋白是Dictyostelium细胞聚集的细胞粘附蛋白，在体内被脂肪酸、肌醇、磷酸盐和乙醇胺标记，表明该蛋白被脂质锚定在膜上。这种脂质对磷脂酰肌醇特异性磷脂酶c不敏感。当用硝酸裂解或进行乙酰水解时，锚点释放的脂质与锥虫变异细胞表面糖蛋白（一种已知的磷脂酰肌醇-聚糖锚点）释放的脂质不同。对弱碱的耐受性和对强碱的敏感性表明，接触位点A糖脂锚点的脂肪酸处于酰胺键中。与鞘磷脂酶孵育后，释放出一种具有神经酰胺色谱行为的脂质。这些结果表明，接触位点A糖蛋白是由一个基于神经酰胺的脂质聚糖锚定的。
The contact site A glycoprotein, a cell adhesion protein of aggregating Dictyostelium cells, was labeled with fatty acid, myo‐inositol, phosphate and ethanolamine in vivo, indicating that the protein is anchored in the membrane by a lipid. This lipid was not susceptible to phosphatidyl inositol specific phospholipase C. When cleaved with nitrous acid or when subjected to acetolysis, the anchor released lipids which were different from those released from Trypanosoma variant cell surface glycoprotein, a protein with a known phosphatidyl inositol‐glycan anchor. Resistance to weak and sensitivity to strong alkali indicated that the fatty acid in the contact site A glycolipid anchor was in an amide bond. On incubation with sphingomyelinase, a lipid with the chromatographic behavior of ceramide was released. These results suggest that the contact site A glycoprotein is anchored by a ceramide based lipid glycan.