Artificial targeting of misfolded cytosolic proteins to endoplasmic reticulum as a mechanism for clearance.
Artificial targeting of misfolded cytosolic proteins to endoplasmic reticulum as a mechanism for clearance.
复制标题
将错误折叠的胞质蛋白人工靶向内质网作为清除机制。
DOI：
10.1038/srep12088
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发表时间：
2015
影响因子：
4.6
通讯作者：
Walters,KylieJ
中科院分区：
文献类型：
--
作者：
Liu,Fen;Koepp,DeannaM;Walters,KylieJ
我们报道错误折叠的细胞质蛋白可以通过引导它们进入内质网（ER）而从哺乳动物细胞中清除。NAT1 R64W和Parkin R42P是天然存在的错误折叠的细胞质酶变体，分别使芳胺乙酰化和泛素化蛋白质。我们证明蛋白酶体抑制引起内质网NAT1 R64W及其泛素化物种的积累，并且这些产物在抑制释放后从细胞中清除。相比之下，NAT1 WT是稳定的，不存在于内质网。Parkin的R42P突变位于与c端结构域相互作用的UBL结构域。Parkin R42P全长蛋白对内质网的转运较差，稳定性较差。有趣的是，将分离的R42P UBL与NAT1 WT融合，会产生一种融合产物，这种融合产物被强劲地输送到内质网并降解。因此，错误折叠的UBL显然被分子内相互作用所掩盖。我们还发现，通过与Sec61β ER定向跨膜结构域的融合，人为地将Parkin R42P定向到ER，可以触发其清除。总之，我们的研究结果表明，将错误折叠的细胞质蛋白输送到内质网可能是一种有效的清除策略。
We report that misfolded cytosolic proteins can be cleared from mammalian cells by directing them to endoplasmic reticulum (ER). NAT1 R64W and Parkin R42P are naturally occurring misfolded variants of cytosolic enzymes that acetylate arylamines and ubiquitinate proteins, respectively. We demonstrate that proteasome inhibition causes ER accumulation of NAT1 R64W and its ubiquitinated species and that these products are cleared from cells following inhibition release. NAT1 WT by contrast is stable and not present at ER. The R42P mutation in Parkin locates to a UBL domain that interacts with C-terminal domains. Parkin R42P full length protein is trafficked poorly to ER and stable. Interestingly, fusion of the isolated R42P UBL to NAT1 WT results in a fusion product that is trafficked robustly to ER and degraded. Thus, the misfolded UBL is apparently masked by the intramolecular interactions. We also find that artificially directing Parkin R42P to ER by fusion with the Sec61β ER-directing transmembrane domain triggers its clearance. Altogether, our results suggest that routing misfolded cytosolic proteins to ER may be an effective strategy for clearance.