Folding of a single domain protein entering the endoplasmic reticulum precedes disulfide formation.
Folding of a single domain protein entering the endoplasmic reticulum precedes disulfide formation.
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DOI：
10.1074/jbc.m117.780742
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发表时间：
2017-04-28
期刊：
影响因子：
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通讯作者：
Bulleid NJ
中科院分区：
文献类型：
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作者：
Robinson PJ;Pringle MA;Woolhead CA;Bulleid NJ
内质网（ER）内蛋白质合成、折叠和二硫键形成之间的关系知之甚少。以前的研究表明，预先存在的二硫键是绝对需要允许蛋白质折叠，相反，蛋白质折叠发生在二硫键形成之前。要解决的问题，首先发生在ER，即蛋白质折叠或二硫键形成，我们研究了折叠事件在早期阶段的多肽链易位到哺乳动物ER使用停滞的翻译中间体。我们的研究结果表明，多肽折叠可以发生没有完整的结构域易位。蛋白质二硫键异构酶（PDI）与这些早期中间体相互作用，但除非蛋白质结构域的整个序列易位，否则不会发生二硫键形成。这是第一个证据表明，折叠的多肽链先于二硫键形成在细胞内的情况下，并强调蛋白质折叠在ER和纯化的蛋白质的重折叠之间的关键差异。
The relationship between protein synthesis, folding, and disulfide formation within the endoplasmic reticulum (ER) is poorly understood. Previous studies have suggested that pre-existing disulfide links are absolutely required to allow protein folding and, conversely, that protein folding occurs prior to disulfide formation. To address the question of what happens first within the ER, that is, protein folding or disulfide formation, we studied folding events at the early stages of polypeptide chain translocation into the mammalian ER using stalled translation intermediates. Our results demonstrate that polypeptide folding can occur without complete domain translocation. Protein disulfide isomerase (PDI) interacts with these early intermediates, but disulfide formation does not occur unless the entire sequence of the protein domain is translocated. This is the first evidence that folding of the polypeptide chain precedes disulfide formation within a cellular context and highlights key differences between protein folding in the ER and refolding of purified proteins.