Singh I N, Sorrentino G, Massarelli R, Kanfer J N
Department of Biochemistry, University of Manitoba, Winnipeg, Canada.
FEBS Lett. 1992 Jan 20;296(2):166-8. doi: 10.1016/0014-5793(92)80371-m.
The presence of sphingosine and oleoylamine in the culture medium of LA-N-2 cells stimulated the incorporation of [3H]serine into its corresponding phospholipid, phosphatidylserine (PtdSer). The optimum stimulation for sphingosine and oleoylamine were 50 microM and 100 microM, respectively. Oleoylamine increased the incorporation of [3H]serine over 6-fold while sphingosine increased the incorporation of [3H]serine over 2.5-fold. The amount of radioactivity found in water-soluble components and in protein was similar to that found with control LA-N-2 cells. The incorporation of [3H]choline and [3H]ethanolamine into their corresponding phospholipids were decreased in the presence of either oleoylamine or sphingosine. A protein kinase C (PKC) activator, DiC8, and a PKC inhibitor, H7, did not influence the enhanced phosphatidylserine formation by sphingosine and oleoylamine. In addition, there were no differences in the stimulatory effect of sphingosine and oleoylamine discernable between PKC down-regulated cells or controls. These observations indicate that this oleoylamine and sphingosine mediated enhanced phosphatidylserine synthesis is PKC-independent.
在LA - N - 2细胞的培养基中，鞘氨醇和油酰基胺的存在刺激了[3H]丝氨酸掺入其相应的磷脂——磷脂酰丝氨酸（PtdSer）。鞘氨醇和油酰基胺的最佳刺激浓度分别为50微摩尔/升和100微摩尔/升。油酰基胺使[3H]丝氨酸的掺入增加了6倍以上，而鞘氨醇使[3H]丝氨酸的掺入增加了2.5倍以上。在水溶性成分和蛋白质中发现的放射性量与对照LA - N - 2细胞中的相似。在存在油酰基胺或鞘氨醇的情况下，[3H]胆碱和[3H]乙醇胺掺入其相应磷脂的量减少。蛋白激酶C（PKC）激活剂DiC8和PKC抑制剂H7不影响鞘氨醇和油酰基胺增强的磷脂酰丝氨酸形成。此外，在PKC下调的细胞或对照之间，鞘氨醇和油酰基胺的刺激作用没有差异。这些观察结果表明，这种油酰基胺和鞘氨醇介导的磷脂酰丝氨酸合成增强与PKC无关。
