心肌肌浆网膜含有膜质微区结构(英文)

Detergent Resistant Microdomains at Cardiac Sarcoplasmic Reticulum Membranes

细胞膜质微区(microdomain)是细胞膜上特殊的结构域,在细胞信号转导和物质运输过程中起着非常重要的作用.绝大多数膜质微区来源于全细胞膜,即包括质膜和细胞器膜.最新研究表明细胞器膜如高尔基体膜也有膜质微区,因此分离了猪心肌浆网膜的膜质微区.首先获得了没有质膜污染的猪心肌浆网,用去污剂TritonX-100处理该肌浆网,获得了去污剂不溶的质膜微区(SR-DRM),该微区富集胆固醇和鞘磷脂.质膜微区的标记脂和蛋白质:神经节苷脂GM1和Caveolin-3也在该区富集.同时还研究了心肌浆网Ca2+-ATPase(SERCA2a)的分布,结果表明,相当数量的SERCA2a分布在膜质微区,并且有正常的生理功能.上述研究结果表明,在心肌浆网膜上有膜质微区的存在,进一步证明膜质微区不仅存在于细胞质膜,也普遍存在于细胞器膜.

It is generally believed that sphingomyelin- and cholesterol-enriched microdomains can be isolated as detergent-resistant membranes （DRMs） from plasma membrane and organelle membranes. Here the isolation of microdomains from porcine cardiac sarcoplasmic reticulum （SR） membranes is described. These SR-derived detergent-resistant membranes （SR-DRMs） enriched in sphingomyelin and cholesterol have a low buoyant density. Both ganglioside GM1 and caveolin-3 in the SR, known as a marker protein ofcaveolae at plasma membrane are present in the SR-DRMs. It was demonstrated that significant amount of SERCAs together with caveolin-3 associates with SR-DRMs, and are fully functional. The results suggested that SR membranes like other biomembranes, such as the plasma membrane, contained microdomains.