NAC and Zuotin/Hsp70 chaperone systems coexist at the ribosome tunnel exit in vivo.
NAC and Zuotin/Hsp70 chaperone systems coexist at the ribosome tunnel exit in vivo.
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NAC 和 Zuotin/Hsp70 伴侣系统在体内共存于核糖体隧道出口处。
DOI：
10.1093/nar/gkae005
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发表时间：
2024
影响因子：
14.9
通讯作者：
Craig,ElizabethA
中科院分区：
文献类型：
--
作者：
Ziegelhoffer,Thomas;Verma,AmitK;Delewski,Wojciech;Schilke,BrendaA;Hill,PaigeM;Pitek,Marcin;Marszalek,Jaroslaw;Craig,ElizabethA
60 S核糖体亚基隧道出口周围的区域是参与新生多肽链成熟和折叠的蛋白质的中心。在复杂的蜂窝环境中，不同的因素如何在隧道出口处竞争定位还没有很好的理解。我们使用活体位点特异性交联来解决这个问题，集中在两个丰富的因子-新生链相关复合物（NAC）和Hsp 70分子伴侣系统，包括J结构域蛋白共分子伴侣Zuotin。我们发现NAC和Zuotin可以在核糖体上相互交联，即使在翻译起始被抑制时。产生NAC-左丁交联的位置表明，当两者都存在时，NAC的中心球状结构域从在低温电子显微镜分析中观察到的互斥位置适度地转移。交联结果还表明，即使在NAC存在的情况下，Hsp 70也可以以有利于产生新生链相互作用的方式定位--肽结合位点位于隧道出口处，而Zuotin的J结构域适当定位以驱动新生链结合的稳定。总体而言，我们的结果是一致的想法，在体内，NAC和热休克蛋白70系统可以有效地定位在核糖体上的同时。
The area surrounding the tunnel exit of the 60S ribosomal subunit is a hub for proteins involved in maturation and folding of emerging nascent polypeptide chains. How different factors vie for positioning at the tunnel exit in the complex cellular environment is not well understood. We usedin vivosite-specific cross-linking to approach this question, focusing on two abundant factors—the nascent chain-associated complex (NAC) and the Hsp70 chaperone system that includes the J-domain protein co-chaperone Zuotin. We found that NAC and Zuotin can cross-link to each other at the ribosome, even when translation initiation is inhibited. Positions yielding NAC–Zuotin cross-links indicate that when both are present the central globular domain of NAC is modestly shifted from the mutually exclusive position observed in cryogenic electron microscopy analysis. Cross-linking results also suggest that, even in NAC’s presence, Hsp70 can situate in a manner conducive for productive nascent chain interaction—with the peptide binding site at the tunnel exit and the J-domain of Zuotin appropriately positioned to drive stabilization of nascent chain binding. Overall, our results are consistent with the idea that,in vivo, the NAC and Hsp70 systems can productively position on the ribosome simultaneously.