Localization of sucrase-isomaltase in the rat enterocyte.
Localization of sucrase-isomaltase in the rat enterocyte.
复制标题
蔗糖酶-异麦芽糖酶在大鼠肠细胞中的定位。
DOI：
10.1016/0016-5085(87)90844-4
复制
发表时间：
1987
期刊：
影响因子：
29.4
通讯作者：
Olsen,WA
中科院分区：
文献类型：
--
作者：
Lorenzsonn,V;Korsmo,H;Olsen,WA
我们利用免疫电子显微镜研究了刷状缘膜内固有糖蛋白蔗糖-异麦糖酶的细胞内定位，以了解其合成和细胞内加工的位点及其向刷状缘膜转移的机制。我们用蛋白a -胶体金包埋后染色和过氧化物酶包埋前染色鉴定该蛋白。该蛋白不仅存在于毛囊边缘膜中，还存在于内质网（包括核膜）、高尔基复合体、光滑的顶泡中，在多泡体中也有不同程度的存在。我们的发现与目前关于质膜蛋白生物合成的概念是一致的，合成、易位和初始糖基化发生在内质网膜上，并在高尔基复合体中进行进一步的加工。这些发现表明可能发生了一些细胞内蔗糖-异麦芽糖酶的降解。最后，我们的研究结果似乎表明，至少细胞内运动的最后一步，即转移到刷状边缘膜，是由光滑的顶膜小泡介导的。
We used immune electron microscopy to study the intracellular localization of sucrase-isomaltase, an intrinsic glycoprotein of the brush border membrane, to provide insight regarding the sites of its synthesis and intracellular processing and the mechanisms of its transfer to the brush border membrane. We identified the protein by postembedding staining with protein A-colloidal gold and by preembedding staining with peroxidase. The protein was found not only in the brush border membrane, but also in the endoplasmic reticulum including nuclear envelope, Golgi complex, smooth apical vesicles, and to a variable extent in the multivesicular bodies. Our findings are consistent with current concepts of biosynthesis of plasma membrane proteins, with synthesis, translocation, and initial glycosylation occurring at the membrane of endoplasmic reticulum and further processing occurring in the Golgi complex. The findings suggest the possibility that some intracellular degradation of sucrase-isomaltase occurs. Finally, our results appear to indicate that at least the final step of intracellular movement, transfer to the brush border membrane, is mediated by smooth apical membrane vesicles.