Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, 9 Cambridge Center, Cambridge, MA 02142, USA.
Trends Cell Biol. 2012 Jan;22(1):22-32. doi: 10.1016/j.tcb.2011.09.010. Epub 2011 Nov 3.
Protein maturation in the endoplasmic reticulum (ER) is subject to stringent quality control. Terminally misfolded polypeptides are usually ejected into the cytoplasm and targeted for destruction by the proteasome. Ubiquitin conjugation is essential for both extraction and proteolysis. We discuss the role of the ubiquitin conjugation machinery in this pathway and focus on the role of ubiquitin ligase complexes as gatekeepers for membrane passage. We then examine the type of ubiquitin modification applied to the misfolded ER protein and the role of de-ubiquitylating enzymes in the extraction of proteins from the ER.
内质网（ER）中的蛋白质成熟受到严格的质量控制。终末错误折叠的多肽通常被排出到细胞质中，并被蛋白酶体靶向破坏。泛素缀合对于提取和蛋白水解都是必不可少的。我们讨论了泛素缀合机制在这条途径中的作用，并重点介绍了泛素连接酶复合物作为膜通道门控的作用。然后，我们研究了应用于错误折叠的 ER 蛋白的泛素修饰类型以及去泛素化酶在从 ER 中提取蛋白质中的作用。
