Shirasu Ken
RIKEN Plant Science Center, Yokohama City, Kanagawa 230-0045, Japan.
Annu Rev Plant Biol. 2009;60:139-64. doi: 10.1146/annurev.arplant.59.032607.092906.
The nucleotide-binding domain and leucine-rich repeat-containing (NLR) proteins function as immune sensors in both plants and animals. NLR proteins recognize, directly or indirectly, pathogen-derived molecules and trigger immune responses. To function as a sensor, NLR proteins must be correctly folded and maintained in a recognition-competent state in the appropriate cellular location. Upon pathogen recognition, conformational changes and/or translocation of the sensors would activate the downstream immunity signaling pathways. Misfolded or used sensors are a threat to the cell and must be immediately inactivated and discarded to avoid inappropriate activation of downstream pathways. Such maintenance of NLR-type sensors requires the SGT1-HSP90 pair, a chaperone complex that is structurally and functionally conserved in eukaryotes. Deciphering how the chaperone machinery works would facilitate an understanding of the mechanisms of pathogen recognition and signal transduction by NLR proteins in both plants and animals.
核苷酸结合结构域富含亮氨酸重复序列（NLR）蛋白在植物和动物中均作为免疫传感器发挥作用。NLR蛋白直接或间接识别病原体衍生分子并触发免疫反应。为了发挥传感器的功能，NLR蛋白必须正确折叠并在适当的细胞位置维持在具有识别能力的状态。病原体识别后，传感器的构象变化和/或易位会激活下游免疫信号通路。错误折叠或用过的传感器对细胞构成威胁，必须立即失活并丢弃，以避免下游通路的不适当激活。这种对NLR型传感器的维持需要SGT1-HSP90对，这是一种在真核生物中结构和功能保守的伴侣蛋白复合体。弄清楚伴侣蛋白机制如何工作将有助于理解植物和动物中NLR蛋白的病原体识别和信号转导机制。
