Roles of intramolecular and intermolecular interactions in functional regulation of the Hsp70 J-protein co-chaperone Sis1.
Roles of intramolecular and intermolecular interactions in functional regulation of the Hsp70 J-protein co-chaperone Sis1.
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DOI：
10.1016/j.jmb.2015.02.007
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发表时间：
2015-04-10
影响因子：
5.6
通讯作者：
Craig, Elizabeth A.
中科院分区：
文献类型：
--
作者：
Yu, Hyun Young;Ziegelhoffer, Thomas;Osipiuk, Jerzy;Ciesielskil, Szymon J.;Baranowski, Maciej;Zhou, Min;Joachimiak, Andrzej;Craig, Elizabeth A.
与其他 Hsp70 分子伴侣不同，真核细胞质的 Hsp70 分子伴侣在其 C 末端有四个残基 EEVD。 EEVD(Hsp70) 结合 Hsp90 伴侣系统的接头蛋白和线粒体膜前蛋白受体，从而通过蛋白质折叠和易位途径促进 Hsp70 结合客户的加工。在这些途径中起作用的 J 蛋白共伴侣中，Sis1 是独特的，因为它还结合 EEVD(Hsp70) 基序。然而，人们对 Sis1:EEVD(Hsp70) 相互作用的作用知之甚少。我们发现，EEVD(Hsp70) 的缺失消除了 Sis1 在体外蛋白质重折叠中与 Hsp70 合作的能力，但并没有消除普遍存在的 J 蛋白 Ydj1。 J 结构域的谷氨酸被取代后，Sis1 与 Hsp70ΔEEVD 的共伴侣活性得以恢复。结构分析表明，Ydj1 中不存在的这一关键谷氨酸与紧邻的富含甘氨酸区域的精氨酸形成盐桥。因此，Sis1 体外活性的恢复表明 J 结构域和富含甘氨酸的区域之间的分子内相互作用控制着共伴侣活性，只有当 Sis1 与 EEVD(Hsp70) 基序相互作用时，这种相互作用才是最佳的。然而，我们发现 Sis1:EEVD(Hsp70) 相互作用的破坏增强了 Sis1 在体内替代 Ydj1 的能力。我们的结果与 Sis1 与 EEVD(Hsp70) 的相互作用最大限度地减少 Sis1 结合客户向 Hsp70 的转移的想法是一致的，而 Hsp70 是通过与 EEVD 结合接头蛋白预结合而为客户转移到折叠和易位途径做好准备的。这些相互作用可能是细胞将 Ydj1 和 Sis1 结合客户分别分类到生产和质量控制途径的一种手段。
Unlike other Hsp70 molecular chaperones, those of the eukaryotic cytosol have four residues, EEVD, at their C-termini. EEVD(Hsp70) binds adaptor proteins of the Hsp90 chaperone system and mitochondrial membrane preprotein receptors, thereby facilitating processing of Hsp70-bound clients through protein folding and translocation pathways. Among J-protein co-chaperones functioning in these pathways Sis1 is unique, as it also binds the EEVD(Hsp70) motif. However, little is known about the role of the Sis1:EEVD(Hsp70) interaction. We found that deletion of EEVD(Hsp70) abolished the ability of Sis1, but not the ubiquitous J-protein Ydj1, to partner with Hsp70 in in vitro protein refolding. Sis1 co-chaperone activity with Hsp70ΔEEVD was restored upon substitution of a glutamic acid of the J-domain. Structural analysis revealed that this key glutamic acid, which is not present in Ydj1, forms a salt bridge with an arginine of the immediately adjacent glycine-rich region. Thus, restoration of Sis1 in vitro activity suggests that intramolecular interaction(s) between the J-domain and glycine-rich region controls co-chaperone activity, which is optimal only when Sis1 interacts with the EEVD(Hsp70) motif. Yet, we found that disruption of the Sis1:EEVD(Hsp70) interaction enhances the ability of Sis1 to substitute for Ydj1 in vivo. Our results are consistent with the idea that interaction of Sis1 with EEVD(Hsp70) minimizes transfer of Sis1-bound clients to Hsp70s that are primed for client transfer to folding and translocation pathways by their preassociation with EEVD-binding adaptor proteins. These interactions may be one means by which cells triage Ydj1- and Sis1-bound clients to productive and quality control pathways, respectively.
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影响因子：
4.1
作者：
Li, Jingzhi;Wu, Yunkun;Sha, Bingdong
通讯作者：
Sha, Bingdong
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
DOI：
10.1083/jcb.114.4.623
发表时间：
1991-08
期刊：
The Journal of cell biology
影响因子：
--
作者：
Luke MM;Sutton A;Arndt KT
通讯作者：
Arndt KT
DOI：
10.1107/s0907444902016657
发表时间：
2002-11-01
影响因子：
2.2
作者：
Adams, PD;Grosse-Kunstleve, RW;Terwilliger, TC
通讯作者：
Terwilliger, TC
影响因子：
10.7
作者：
Sahi, Chandan;Kominek, Jacek;Craig, Elizabeth A.
通讯作者：
Craig, Elizabeth A.