Hermesh Orit, Jansen Ralf-Peter
Interfaculty Institute for Biochemistry, Eberhard-Karls-Universität Tübingen, Tübingen, Germany.
Biochim Biophys Acta. 2013 Nov;1833(11):2519-25. doi: 10.1016/j.bbamcr.2013.01.013. Epub 2013 Jan 23.
Protein translocation into the endoplasmic reticulum (ER) generally requires targeting of mRNAs encoding secreted or membrane proteins to the ER membrane. The prevalent view is that these mRNAs are delivered co-translationally, using the signal recognition particle (SRP) pathway. Here, SRP delivers signal sequence-containing proteins together with associated ribosomes and mRNA to the SRP receptor present on the ER surface. Recent studies demonstrate the presence of alternative pathways to recruit mRNAs to ER or to specific subdomains of the ER independent of SRP or translation. Such targeting of specific mRNAs to the ER subdomains allows the cell to sort proteins before translocation or to ensure co-localization of ER and mRNAs at specific locations. Translation-independent association of mRNAs involves ER-linked RNA-binding proteins and represents an alternative pathway of mRNA delivery to the ER. This article is part of a Special Issue entitled: Functional and structural diversity of endoplasmic reticulum.
蛋白质转运到内质网（ER）通常需要将编码分泌蛋白或膜蛋白的mRNA靶向内质网膜。普遍的观点是，这些mRNA通过信号识别颗粒（SRP）途径进行共翻译转运。在这里，SRP将含有信号序列的蛋白质与相关核糖体和mRNA一起递送至内质网表面的SRP受体。最近的研究表明，存在不依赖SRP或翻译的将mRNA招募到内质网或内质网特定亚结构域的替代途径。将特定mRNA靶向内质网亚结构域可使细胞在转运前对蛋白质进行分选，或确保内质网和mRNA在特定位置共定位。mRNA的非翻译依赖性结合涉及内质网相关的RNA结合蛋白，代表了mRNA递送至内质网的另一种途径。本文是名为：内质网的功能和结构多样性的特刊的一部分。
