Structure and assembly of the endoplasmic reticulum. Biosynthetic sorting of endoplasmic reticulum proteins.
Structure and assembly of the endoplasmic reticulum. Biosynthetic sorting of endoplasmic reticulum proteins.
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DOI：
10.1016/s0021-9258(18)88868-8
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发表时间：
1985-06
期刊：
影响因子：
--
通讯作者：
M. Lewis;S. Turco;M. Green
中科院分区：
文献类型：
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作者：
M. Lewis;S. Turco;M. Green
我们研究了小鼠内质网ERp60、ERp72和ERp99三种蛋白组分的翻译后加工和生物合成分选。在脉冲标记的MOPC-315（其中MOPC-315代表矿物油诱导的浆细胞）浆细胞瘤细胞中，没有检测到这些蛋白的前体形式，只有ERp99对内糖苷酶H敏感。在3小时的追踪过程中，ERp99寡糖仍对内糖苷酶H敏感，高效液相色谱分析显示其主要结构为Man8GlcNAc2。我们对脉冲标记的MOPC-315浆细胞瘤细胞进行蔗糖梯度分析，以直接研究糖基化和非糖基化ERps的生物合成分选，并没有发现强有力的证据表明这些蛋白质曾经离开内质网。尽管它们有共同的分选途径，但这些蛋白质的膜取向不同。ERp60和ERp72都完全受到内质网膜的保护，而ERp99似乎在内质网的细胞质面暴露了一个大的结构域。
We have studied the post-translational processing and the biosynthetic sorting of three protein components of murine endoplasmic reticulum (ER), ERp60, ERp72, and ERp99. In pulse-labeled MOPC-315 (where MOPC-315 represents mineral oil-induced plasmacytoma cells) plasmacytoma cells, no precursor forms of these proteins were detected and only ERp99 was sensitive to endoglycosidase H. The ERp99 oligosaccharide remained endoglycosidase H sensitive during a 3-h chase, and analysis by high performance liquid chromatography showed the predominant structure to be Man8GlcNAc2. We have used a sucrose gradient analysis of pulse-labeled MOPC-315 plasmacytoma cells in order to directly study the biosynthetic sorting of both glycosylated and nonglycosylated ERps and have found no strong evidence to suggest these proteins ever leave the endoplasmic reticulum. In spite of their common sorting pathway, these proteins differ in their membrane orientation. Both ERp60 and ERp72 are entirely protected by the endoplasmic reticulum membrane while ERp99 appears to have a large domain exposed on the cytoplasmic face of the endoplasmic reticulum.