Itskanov Samuel, Park Eunyong
Biophysics Graduate Program.
California Institute for Quantitative Biosciences.
Cold Spring Harb Perspect Biol. 2023 Jan 3;15(1):a041250. doi: 10.1101/cshperspect.a041250.
The endoplasmic reticulum (ER) is a major site for protein synthesis, folding, and maturation in eukaryotic cells, responsible for production of secretory proteins and most integral membrane proteins. The universally conserved protein-conducting channel Sec61 complex mediates core steps in these processes by translocating hydrophilic polypeptide segments of client proteins across the ER membrane and integrating hydrophobic transmembrane segments into the membrane. The Sec61 complex associates with several other molecular machines and enzymes to enable substrate engagement with the channel and coordination of protein translocation with translation, protein folding, and/or post-translational modifications. Recent cryo-electron microscopy and functional studies of these translocon complexes have greatly advanced our mechanistic understanding of Sec61-dependent protein biogenesis at the ER. Here, we will review the current models for how the Sec61 channel performs its functions in coordination with partner complexes.
内质网（ER）是真核细胞中蛋白质合成、折叠和成熟的主要场所，负责分泌蛋白和大多数整合膜蛋白的产生。普遍保守的蛋白质传导通道Sec61复合物通过将客户蛋白的亲水性多肽片段转运穿过内质网膜并将疏水性跨膜片段整合到膜中，介导这些过程中的核心步骤。Sec61复合物与其他几种分子机器和酶结合，以使底物与通道结合，并使蛋白质转运与翻译、蛋白质折叠和/或翻译后修饰相协调。最近对这些转位子复合物的冷冻电子显微镜和功能研究极大地推进了我们对内质网中Sec61依赖性蛋白质生物合成机制的理解。在这里，我们将综述目前关于Sec61通道如何与伴侣复合物协同发挥功能的模型。
