Takahashi Akira, Casais Catarina, Ichimura Kazuya, Shirasu Ken
The Sainsbury Laboratory, John Innes Centre, Colney Lane, Norwich NR4 7UH, United Kingdom.
Proc Natl Acad Sci U S A. 2003 Sep 30;100(20):11777-82. doi: 10.1073/pnas.2033934100. Epub 2003 Sep 22.
RAR1 and its interacting partner SGT1 play a central role in plant disease resistance triggered by a number of resistance (R) proteins. We identified cytosolic heat shock protein 90 (HSP90), a molecular chaperone, as another RAR1 interacting protein by yeast two-hybrid screening. RAR1 interacts with the N-terminal half of HSP90 that contains the ATPase domain. HSP90 also specifically interacts with SGT1 that contains a tetratricopeptide repeat motif and a domain with similarity to the cochaperone p23. In Arabidopsis, the HSP90 inhibitor geldanamycin reduces the hypersensitive response and abolishes resistance triggered by the R protein RPS2 against Pseudomonas syringae pv. tomato DC3000 (avrRpt2). One of four Arabidopsis cytosolic HSP90 isoforms, AtHSP90.1 is required for full RPS2 resistance and is rapidly induced upon pathogen challenge. We propose that RAR1 and SGT1 function closely with HSP90 in chaperoning roles that are essential for disease resistance.
RAR1及其相互作用伴侣SGT1在多种抗性（R）蛋白引发的植物抗病性中发挥核心作用。我们通过酵母双杂交筛选，鉴定出分子伴侣胞质热休克蛋白90（HSP90）为另一种与RAR1相互作用的蛋白。RAR1与包含ATP酶结构域的HSP90的N端半段相互作用。HSP90还与包含四肽重复基序和与伴侣蛋白p23相似结构域的SGT1特异性相互作用。在拟南芥中，HSP90抑制剂格尔德霉素可降低过敏反应，并消除R蛋白RPS2对丁香假单胞菌番茄致病变种DC3000（avrRpt2）引发的抗性。拟南芥四种胞质HSP90亚型之一的AtHSP90.1是RPS2完全抗性所必需，并在病原体攻击后迅速被诱导。我们提出，RAR1和SGT1在对抗病性至关重要的伴侣作用中与HSP90密切协作。
