Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada.
Appl Physiol Nutr Metab. 2012 Aug;37(4):724-35. doi: 10.1139/h2012-059. Epub 2012 Jun 5.
Proteins that coat the lipid droplets (also known as PAT proteins or perilipin (PLIN) family proteins) have diverse functions that are not well elucidated in many tissues. In skeletal muscle, there is even less known about the functions or characteristics of these proteins or how they might change in response to perturbations that alter both intramyocellular lipid (IMCL) content and fat utilization and oxidation. Therefore, the purpose of this study was to examine the human muscle content and gene expression of the four skeletal muscle PLIN proteins in both lean and obese men and women and how this was changed following a 12-week endurance training protocol. PLIN2-PLIN5 proteins were all more abundant in women than in men (p = 0.037 and p < 0.0001, respectively), consistent with higher IMCL content observed in female skeletal muscle. PLIN5 (previously known as OXPAT) is of particular interest because it has previously been associated primarily with oxidative tissues that rely heavily on fat oxidation for energy production. Although PLIN5 was not different between lean and obese subjects, it was the only PLIN protein to increase in response to endurance training in both sexes. PLIN5 correlated with IMCL volume (p < 0.0001), but in general, the other PLIN proteins did not correlate well with IMCL volume, suggesting that the relationship between lipid accumulation and PLIN family protein content is not a simple one. Although more work is necessary, it is clear that PLIN5 likely plays an important role in IMCL accumulation and oxidation, both of which increase with endurance training in human skeletal muscle.
覆盖脂滴的蛋白质（也称为 PAT 蛋白或 perilipin（PLIN）家族蛋白）具有多种功能，但在许多组织中尚未得到充分阐明。在骨骼肌中，人们对这些蛋白质的功能或特征知之甚少，也不知道它们如何在改变细胞内脂质（IMCL）含量以及脂肪利用和氧化的干扰下发生变化。因此，本研究的目的是检测瘦人和肥胖男女的四种骨骼肌 PLIN 蛋白在人类肌肉中的含量和基因表达情况，以及在 12 周耐力训练方案后这些蛋白如何发生变化。PLIN2-PLIN5 蛋白在女性中的含量均高于男性（p=0.037 和 p<0.0001），与女性骨骼肌中观察到的较高 IMCL 含量一致。PLIN5（以前称为 OXPAT）特别有趣，因为它以前主要与依赖脂肪氧化产生能量的氧化组织有关。尽管 PLIN5 在瘦人和肥胖人群之间没有差异，但它是唯一一种在两性中对耐力训练有反应而增加的 PLIN 蛋白。PLIN5 与 IMCL 体积呈正相关（p<0.0001），但总体而言，其他 PLIN 蛋白与 IMCL 体积相关性较差，这表明脂质积累与 PLIN 家族蛋白含量之间的关系并非简单的一一对应关系。尽管还需要做更多的工作，但很明显，PLIN5 可能在 IMCL 的积累和氧化中发挥重要作用，而这两者在人类骨骼肌中都随着耐力训练而增加。
