MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK.
MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK.
Curr Biol. 2018 Apr 23;28(8):R498-R511. doi: 10.1016/j.cub.2018.02.004.
One-fourth of eukaryotic genes code for integral membrane proteins, nearly all of which are inserted and assembled at the endoplasmic reticulum (ER). The defining feature of membrane proteins is one or more transmembrane domains (TMDs). During membrane protein biogenesis, TMDs are selectively recognized, shielded, and chaperoned into the lipid bilayer, where they often assemble with other TMDs. If maturation fails, exposed TMDs serve as a cue for engagement of degradation pathways. Thus, TMD-recognition factors in the cytosol and ER are essential for membrane protein biogenesis and quality control. Here, we discuss the growing assortment of cytosolic and membrane-embedded TMD-recognition factors, the pathways within which they operate, and mechanistic principles of recognition.
四分之一的真核基因编码整合膜蛋白，几乎所有这些蛋白都在内质网（ER）中插入和组装。膜蛋白的定义特征是一个或多个跨膜结构域（TMD）。在膜蛋白生物发生过程中，TMD 被选择性识别、屏蔽，并被伴侣蛋白引导进入脂质双层，在那里它们通常与其他 TMD 组装。如果成熟失败，暴露的 TMD 则作为参与降解途径的信号。因此，细胞质和 ER 中的 TMD 识别因子对于膜蛋白的生物发生和质量控制是必不可少的。在这里，我们讨论了不断增加的细胞质和膜嵌入 TMD 识别因子，它们作用的途径以及识别的机制原理。
