hRpn13/ADRM1/GP110 is a novel proteasome subunit that binds the deubiquitinating enzyme, UCH37
hRpn13/ADRM1/GP110 is a novel proteasome subunit that binds the deubiquitinating enzyme, UCH37
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DOI：
10.1038/sj.emboj.7601450
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发表时间：
2006-12-13
期刊：
影响因子：
11.4
通讯作者：
Goldberg, Alfred L.
中科院分区：
文献类型：
--
作者：
Qiu, Xiao-Bo;Ouyang, Song-Ying;Goldberg, Alfred L.
26S 蛋白酶体催化哺乳动物细胞中大多数蛋白质的降解。为了更好地确定其组成和相关的调节蛋白，我们开发了亲和方法来快速从哺乳动物细胞中纯化 26S 蛋白酶体。通过这种方法，我们发现了其 19S 调节复合物（以前称为 ADRM1 或 GP110）的一个新的 46-kDa（407 个残基）亚基。由于其 N 端一半可以整合到 26S 蛋白酶体中，并且与芽殖酵母中 19S 复合物的 156 个残基亚基 Rpn13 同源，我们将其重命名为人 Rpn13 (hRpn13)。 hRpn13 的 C 端一半直接与蛋白酶体相关的去泛素化酶 UCH37 结合，并增强其肽酶活性。 293T 细胞中 hRpn13 的敲低会增加泛素缀合物的细胞水平并减少短寿命蛋白质的降解。令人惊讶的是，hRpn13 的过量产生也减少了它们的降解。此外，hRpn13 C 端一半的转染会减慢蛋白水解并诱导细胞死亡，这可能是通过作为显性失活形式发挥作用。因此，在人 26S 蛋白酶体中，hRpn13 似乎对于 UCH37 与 19S 复合物的结合以及有效的蛋白水解很重要。
The 26S proteasome catalyzes the degradation of most proteins in mammalian cells. To better define its composition and associated regulatory proteins, we developed affinity methods to rapidly purify 26S proteasomes from mammalian cells. By this approach, we discovered a novel 46-kDa (407 residues) subunit of its 19S regulatory complex (previously termed ADRM1 or GP110). As its N-terminal half can be incorporated into the 26S proteasome and is homologous to Rpn13, a 156-residue subunit of the 19S complex in budding yeast, we renamed it human Rpn13 (hRpn13). The C-terminal half of hRpn13 binds directly to the proteasome-associated deubiquitinating enzyme, UCH37, and enhances its isopeptidase activity. Knockdown of hRpn13 in 293T cells increases the cellular levels of ubiquitin conjugates and decreases the degradation of short-lived proteins. Surprisingly, an overproduction of hRpn13 also reduced their degradation. Furthermore, transfection of the C-terminal half of hRpn13 slows proteolysis and induces cell death, probably by acting as a dominant-negative form. Thus in human 26S proteasomes, hRpn13 appears to be important for the binding of UCH37 to the 19S complex and for efficient proteolysis.