The quote "bring it back, bring it back, don't take it away from me" from Queen's Love of my life describes the function of the sorting receptor RER1, a 23 kDa protein with four transmembrane domains (TMDs) that localizes to the intermediate compartment and the cis-Golgi. From there it returns escaped proteins that are not supposed to leave the endoplasmic reticulum (ER) back to it. Unique about RER1 is its ability to recognize its ligands through binding motifs in TMDs. Among its substrates are ER-resident proteins, as well as unassembled subunits of multimeric complexes that are retrieved back into the ER, this way guarding the full assembly of their respective complexes. The basic mechanisms for RER1-dependent retrieval have been already elucidated some years ago in yeast. More recently, several important cargoes of RER1 have been described in mammalian cells, and the in vivo role of RER1 is being unveiled by using mouse models. In this Review, we give an overview of the cell biology of RER1 in different models, discuss its controversial role in the brain and provide an outlook on future directions for RER1 research.

中文翻译：

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带回来，带回来，别从我这里拿走——分拣接收器RER1。

来自 Queen's Love of my life 的引述“带回来，带回来，不要把它从我身边带走”描述了分选受体 RER1 的功能，这是一种具有四个跨膜结构域 (TMD) 的 23 kDa 蛋白质，定位于中间室和顺式高尔基体。它从那里返回不应离开内质网 (ER) 的逃逸蛋白质。RER1 的独特之处在于它能够通过 TMD 中的结合基序识别其配体。它的底物包括内质网驻留蛋白，以及未组装的多聚体复合物亚基，这些亚基被回收到内质网中，这样可以保护它们各自复合物的完整组装。几年前已经在酵母中阐明了 RER1 依赖性检索的基本机制。最近，已经在哺乳动物细胞中描述了几种重要的 RER1 货物，并且正在使用小鼠模型揭示 RER1 的体内作用。在这篇综述中，我们概述了不同模型中 RER1 的细胞生物学，讨论了其在大脑中的有争议的作用，并展望了 RER1 研究的未来方向。