Shaw Christopher S, Sherlock Mark, Stewart Paul M, Wagenmakers Anton J M
Exercise Metabolism Research Group, School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
Histochem Cell Biol. 2009 May;131(5):575-81. doi: 10.1007/s00418-009-0558-4. Epub 2009 Jan 24.
Intramyocellular lipids (IMCL) are stored as discrete lipid droplets which are associated with a number of proteins. The lipid droplet-associated protein adipophilin (the human orthologue of adipose differentiation-related protein) is ubiquitously expressed and is one of the predominant lipid droplet-proteins in skeletal muscle. The aim of this study was to investigate the subcellular distribution of adipophilin in human muscle fibres and to measure the colocalization of adipophilin with IMCL. Muscle biopsies from six lean male cyclists (BMI 23.4 +/- 0.4, aged 31 +/- 2 years, W (max) 346 +/- 8) were stained for myosin heavy chain type 1, IMCL, adipophilin and mitochondria using immunofluorescence and viewed with widefield and confocal fluorescence microscopy. The present study shows that like IMCL, the adipophilin content is ~twofold greater in type I skeletal muscle fibres and is situated in the areas between the mitochondrial network. Colocalization analysis demonstrated that 61 +/- 2% of IMCL contain adipophilin. Although the majority of adipophilin is contained within IMCL, 36 +/- 4% of adipophilin is not associated with IMCL. In conclusion, this study indicates that the IMCL pool is heterogeneous, as the majority but not all IMCL contain adipophilin.
肌内脂质（IMCL）以离散的脂滴形式储存，这些脂滴与多种蛋白质相关。脂滴相关蛋白脂联素（脂肪分化相关蛋白的人类同源物）在全身广泛表达，是骨骼肌中主要的脂滴蛋白之一。本研究的目的是研究脂联素在人类肌纤维中的亚细胞分布，并测量脂联素与IMCL的共定位情况。对6名瘦体重男性自行车运动员（体重指数23.4±0.4，年龄31±2岁，最大摄氧量346±8）的肌肉活检组织进行免疫荧光染色，检测1型肌球蛋白重链、IMCL、脂联素和线粒体，并用宽视野和共聚焦荧光显微镜观察。本研究表明，与IMCL一样，脂联素在I型骨骼肌纤维中的含量约高两倍，且位于线粒体网络之间的区域。共定位分析表明，61±2%的IMCL含有脂联素。虽然大部分脂联素存在于IMCL中，但36±4%的脂联素与IMCL无关。总之，本研究表明IMCL库是异质性的，因为大部分但并非所有的IMCL都含有脂联素。
