Römisch Karin
University of Cambridge, Cambridge Institute for Medical Research and Department of Clinical Biochemistry, Hills Road, Cambridge CB2 2XY, UK.
Trends Biochem Sci. 2006 Jan;31(1):24-5. doi: 10.1016/j.tibs.2005.11.004. Epub 2005 Nov 28.
Proteasome-mediated turnover of misfolded secretory and transmembrane proteins at the cytoplasmic face of the endoplasmic reticulum (ER) membrane is dependent on a AAA-ATPase complex formed by the ubiquitin-selective chaperone Cdc48p in Saccharomyces cerevisiae and mammals by the Cdc48p homologue p97. Two new papers reveal that the Ubx2 protein physically links ER-membrane-integrated ubiquitin ligases to Cdc48p, and that it is essential for degradation of substrates that are ubiquitylated at the cytoplasmic face of the ER.
在内质网（ER）膜细胞质面，蛋白酶体介导的错误折叠分泌蛋白和跨膜蛋白的周转依赖于酿酒酵母中由泛素选择性伴侣蛋白Cdc48p形成的AAA-ATP酶复合物，在哺乳动物中则依赖于Cdc48p同源物p97。两篇新论文揭示，Ubx2蛋白在物理上把内质网膜整合的泛素连接酶与Cdc48p联系起来，并且它对于在内质网细胞质面被泛素化的底物的降解至关重要。
