Klein A, Henseler M, Klein C, Suzuki K, Harzer K, Sandhoff K
Institut für Organische Chemie und Biochemie, Universität Bonn, Germany.
Biochem Biophys Res Commun. 1994 May 16;200(3):1440-8. doi: 10.1006/bbrc.1994.1612.
Glycosphingolipids of cultured fibroblasts from patients with total sphingolipid activator proteins (SAPs) deficiency (Schnabel et al. J. Biol. Chem. 267:3312-3315, 1992) were labeled biosynthetically with [14C]serine. After a chase period of 120h the patients' fibroblasts showed increased labeling of ceramide, glucosylceramide, lactosylceramide and ganglioside GM3 in comparison to normal control cells. Addition of sap-D to the chase-media of the patients' fibroblasts led to the degradation of the accumulated ceramide down to nearly normal levels, whereas the levels of other labeled sphingolipids remained unaffected. In contrast, addition of sap-B to the chase-media of the patients' fibroblasts did not reduce the increased ceramide levels but resulted, as expected from in vitro experiments, in a specific decrease of levels of lactosylceramide and ganglioside GM3. Therefore, we conclude that sap-D stimulates in vivo the lysosomal degradation of ceramide.
来自完全缺乏鞘脂激活蛋白（SAPs）患者的培养成纤维细胞的糖鞘脂（施纳贝尔等人，《生物化学杂志》267:3312 - 3315，1992）用[14C]丝氨酸进行生物合成标记。在120小时的追踪期后，与正常对照细胞相比，患者的成纤维细胞显示神经酰胺、葡糖神经酰胺、乳糖基神经酰胺和神经节苷脂GM3的标记增加。向患者成纤维细胞的追踪培养基中添加sap - D导致积累的神经酰胺降解至接近正常水平，而其他标记鞘脂的水平保持不变。相反，向患者成纤维细胞的追踪培养基中添加sap - B并没有降低升高的神经酰胺水平，但正如体外实验所预期的那样，导致乳糖基神经酰胺和神经节苷脂GM3水平特异性降低。因此，我们得出结论，sap - D在体内刺激神经酰胺的溶酶体降解。
