Arabidopsis immunophilins ROF1 (AtFKBP62) and ROF2 (AtFKBP65) exhibit tissue specificity, are heat-stress induced, and bind HSP90
Arabidopsis immunophilins ROF1 (AtFKBP62) and ROF2 (AtFKBP65) exhibit tissue specificity, are heat-stress induced, and bind HSP90
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DOI：
10.1007/s11103-006-9085-z
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发表时间：
2007-01-01
影响因子：
5.1
通讯作者：
Breiman, Adina
中科院分区：
文献类型：
--
作者：
Aviezer-Hagai, Keren;Skovorodnikova, Julia;Breiman, Adina
植物辅助伴侣 FK506 结合蛋白 (FKBP) 是肽基脯氨酰顺反异构酶，在蛋白质折叠、信号转导和伴侣活性中发挥作用。我们报告了拟南芥大 FKBP ROF1 (AtFKBP62) 和 ROF2 (AtFKBP65) 表达和蛋白质积累模式的特征。表达与 GUS 报告基因融合的 ROF1 启动子的转基因植物表明 ROF1 表达具有器官特异性。在根的维管成分、叶的水囊和毛状体以及柱头、萼片和花药中观察到高表达。 ROF1和ROF2的组织特异性和时间表达表明它们受到发育调节。尽管 ROF1 和 ROF2 有 85% 的同一性，但它们响应热应激的表达受到不同的调节。这两个基因在暴露于 37°C 的植物中均被诱导，但只有 ROF2 是真正的热应激蛋白，当植物在 22°C 下生长时无法检测到。ROF1/ROF2 蛋白在 37°C 下积累，在 22°C 恢复后至少保持稳定 4 小时，而在 22°C 下 1 小时后，它们的 mRNA 水平降低。通过蛋白质相互作用测定，证明， ROF1是HSP90的新伙伴。被确定为哺乳动物伴侣和 HSP90 之间的识别和相互作用所必需的五个氨基酸在植物 ROF1-HSP90 中是保守的。我们建议 ROF/HSP90 复合物在体内组装。我们认为 HSP90 和 ROF 同种型之间的特定复合物形成取决于它们的空间和时间表达。此类复合物可能受到环境条件（例如热应激）或内部线索（例如不同激素）的调节。
The plant co-chaperones FK506-binding proteins (FKBPs) are peptidyl prolyl cis-trans isomerases that function in protein folding, signal transduction and chaperone activity. We report the characterization of the Arabidopsis large FKBPs ROF1 (AtFKBP62) and ROF2 (AtFKBP65) expression and protein accumulation patterns. Transgenic plants expressing ROF1 promoter fused to GUS reporter gene reveal that ROF1 expression is organ specific. High expression was observed in the vascular elements of roots, in hydathodes and trichomes of leaves and in stigma, sepals, and anthers. The tissue specificity and temporal expression of ROF1 and ROF2 show that they are developmentally regulated. Although ROF1 and ROF2 share 85% identity, their expression in response to heat stress is differentially regulated. Both genes are induced in plants exposed to 37 degrees C, but only ROF2 is a bonafide heat-stress protein, undetected when plants are grown at 22 degrees C. ROF1/ROF2 proteins accumulate at 37 degrees C, remain stable for at least 4 h upon recovery at 22 degrees C, whereas, their mRNA level is reduced after 1 h at 22 degrees C. By protein interaction assays, it was demonstrated, that ROF1 is a novel partner of HSP90. The five amino acids identified as essential for recognition and interaction between the mammalian chaperones and HSP90 are conserved in the plant ROF1-HSP90. We suggest that ROF/HSP90 complexes assemble in vivo. We propose that specific complexes formation between an HSP90 and ROF isoforms depends on their spatial and temporal expression. Such complexes might be regulated by environmental conditions such as heat stress or internal cues such as different hormones.