Structural and functional analysis of SGT1 reveals that its interaction with HSP90 is required for the accumulation of Rx, an R protein involved in plant immunity
Structural and functional analysis of SGT1 reveals that its interaction with HSP90 is required for the accumulation of Rx, an R protein involved in plant immunity
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DOI：
10.1105/tpc.107.050427
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发表时间：
2007-11-01
期刊：
影响因子：
11.6
通讯作者：
Guerois, Raphael
中科院分区：
文献类型：
--
作者：
Boter, Marta;Amigues, Beatrice;Guerois, Raphael
SGT1(Skp1的G2等位基因抑制因子)和RAR1(Mla12抗性所需的RAR1)是高度保守的真核蛋白，它们与分子伴侣HSP90(热休克蛋白90)相互作用。在植物中，SGT1、RAR1和HSP90是由许多抗性(R)蛋白触发的抗病所必需的。在这里，我们介绍了植物SGT1蛋白的结构和功能特征。对拟南芥SGT1b的随机诱变表明，其CS(针对Chord-SGT1)和SGS(针对SGT1特异性)结构域是抗病所必需的。基于核磁共振的相互作用表面图谱和CS结构域的突变分析表明，RAR1的Chord II结构域和HSP90的N-末端结构域与CS结构域的对侧相互作用。对CS突变的功能分析表明，SGT1和HSP90之间的相互作用是积累马铃薯(Solanum Tuberosum)R蛋白Rx所必需的。生化重组实验表明，RAR1可能通过促进三元复合体的形成来增强SGT1-HSP90的相互作用。
SGT1 (for suppressor of G2 allele of skp1) and RAR1 (for required for Mla12 resistance) are highly conserved eukaryotic proteins that interact with the molecular chaperone HSP90 (for heat shock protein90). In plants, SGT1, RAR1, and HSP90 are essential for disease resistance triggered by a number of resistance (R) proteins. Here, we present structural and functional characterization of plant SGT1 proteins. Random mutagenesis of Arabidopsis thaliana SGT1b revealed that its CS (for CHORD-SGT1) and SGS (for SGT1 specific) domains are essential for disease resistance. NMR-based interaction surface mapping and mutational analyses of the CS domain showed that the CHORD II domain of RAR1 and the N-terminal domain of HSP90 interact with opposite sides of the CS domain. Functional analysis of the CS mutations indicated that the interaction between SGT1 and HSP90 is required for the accumulation of Rx, a potato (Solanum tuberosum) R protein. Biochemical reconstitution experiments suggest that RAR1 may function to enhance the SGT1-HSP90 interaction by promoting ternary complex formation.