Subcellular distribution of sphingomyelin in 3T3-F442A adipocytes.

*P<0.05
**P<0.01; SM-treated cells compared with control cells. Abbreviations: post-nuclear supernatant (PNS), plasma membrane (PM) fraction, non-caveolae membrane/non-lipid raft (NCM) fraction, caveolae membrane/lipid raft (CM) fraction. PNS represents the fraction of the cells without nuclei including cytosol, microsomes, membranes and others.
Cells were treated with SM-LA (15 μM) for the indicated incubation times. The results, which are expressed as μg of SM per mg protein, are presented as percentages of control cells and are the mean±SEM of three independent experiments. The SM content of plasma membranes was 30±2 μg/mg protein in control adipocytes. The caveolae fraction represents approximately one-third (0.36) of the plasma membrane [78].

*P<0.05，**P<0.01；所有统计显著性均基于SM处理组细胞与对照组细胞的比较。缩写说明：核上清液（post-nuclear supernatant, PNS）、质膜（plasma membrane, PM）组分、非窖蛋白膜/非脂筏（non-caveolae membrane/non-lipid raft, NCM）组分、窖蛋白膜/脂筏（caveolae membrane/lipid raft, CM）组分。PNS指去除细胞核的细胞组分，包含细胞质、微粒体、膜结构及其他成分。
细胞经SM-LA（15 μM）处理指定孵育时长。实验结果以每毫克蛋白对应的SM质量（μg）表示，以对照组细胞的检测值为基准换算为百分比，数据为三次独立实验的平均值±标准误（standard error of the mean, SEM）。对照组脂肪细胞的质膜SM含量为30±2 μg/mg蛋白。窖蛋白组分约占质膜总量的三分之一（0.36）[78]。