Uncoupling retro-translocation and degradation in the ER-associated degradation of a soluble protein
Uncoupling retro-translocation and degradation in the ER-associated degradation of a soluble protein
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DOI：
10.1038/sj.emboj.7600232
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发表时间：
2004-06-02
期刊：
影响因子：
11.4
通讯作者：
Brodsky, JL
中科院分区：
文献类型：
--
作者：
Lee, RJ;Liu, CW;Brodsky, JL
内质网（ER）中的异常多肽通过内质网相关降解（ERAD）被26S蛋白酶体反向转运到细胞质中。为了开始解决ERAD过程中逆向易位和降解步骤的要求，我们使用无细胞试验来研究酵母胞浆和er来源微粒体中特定因子在模型可溶性多肽ERAD过程中的作用。当细胞质伴侣活性受损时，ERAD不受影响，我们询问蛋白酶体本身是否支持该系统的输出和降解。如果用纯化的酵母或哺乳动物蛋白酶体代替野生型细胞质，可以观察到ERAD。此外，仅添加蛋白酶体的19S帽就催化了多肽底物的atp依赖性输出，随后添加20S颗粒后，多肽底物被降解。
Aberrant polypeptides in the endoplasmic reticulum ( ER) are retro-translocated to the cytoplasm and degraded by the 26S proteasome via ER-associated degradation (ERAD). To begin to resolve the requirements for the retro-translocation and degradation steps during ERAD, a cell-free assay was used to investigate the contributions of specific factors in the yeast cytosol and in ER-derived microsomes during the ERAD of a model, soluble polypeptide. As ERAD was unaffected when cytoplasmic chaperone activity was compromised, we asked whether proteasomes on their own supported both export and degradation in this system. Proficient ERAD was observed if wild-type cytosol was substituted with either purified yeast or mammalian proteasomes. Moreover, addition of only the 19S cap of the proteasome catalyzed ATP-dependent export of the polypeptide substrate, which was degraded upon subsequent addition of the 20S particle.