研究揭示植物免疫受體功能發揮機制
作者：
小柯機器人發布時間：2019/8/23 13:56:51
近日，美國科羅拉多州立大學、北卡羅來納大學和華盛頓大學的研究人員合作取得一項新進展。他們發現植物免疫受體的TIR結構域是促進細胞死亡的NAD+裂解酶。該項研究成果發表在2019年8月23日出版的《科學》上。
研究人員證明NLR的植物Toll /白細胞介素-1受體（TIR）結構域是能夠以其氧化形式（NAD+）降解煙醯胺腺嘌呤二核苷酸的酶。植物TIR結構域的細胞死亡誘導和NAD+切割活性都需要已知的自結合界面和假定的催化穀氨酸，這個位點在細菌TIR NAD +切割酶（NADases）和哺乳動物SARM1（sterile alpha and TIR motif containing 1）中都是保守的。研究人員鑑定到一個環磷酸二磷酸核糖的變體可作為TIR酶活性的生物標誌物。TIR酶活性由病原體識別所誘導，並在EDS1（enhanced disease susceptibility 1）和NRG1（N requirement gene 1）的上遊發揮功能，這兩個基因編碼TIR免疫功能所需的調節蛋白。因此，植物TIR-NLR受體需要NADase功能來將病原體識別轉化為細胞死亡反應。
據了解，植物NLR（nucleotide-binding leucine-rich repeat）免疫受體通過未知機制激活細胞死亡並賦予疾病抗性。
附：英文原文
Title: TIR domains of plant immune receptors are NAD+-cleaving enzymes that promote cell death
Author: Li Wan, Kow Essuman, Ryan G. Anderson, Yo Sasaki, Freddy Monteiro, Eui-Hwan Chung, Erin Osborne Nishimura, Aaron DiAntonio, Jeffrey Milbrandt, Jeffery L. Dangl, Marc T. Nishimura
Issue&Volume: Volume 365 Issue 6455
Abstract: Plant nucleotide-binding leucine-rich repeat (NLR) immune receptors activate cell death and confer disease resistance by unknown mechanisms. We demonstrate that plant Toll/interleukin-1 receptor (TIR) domains of NLRs are enzymes capable of degrading nicotinamide adenine dinucleotide in its oxidized form (NAD+). Both cell death induction and NAD+ cleavage activity of plant TIR domains require known self-association interfaces and a putative catalytic glutamic acid that is conserved in both bacterial TIR NAD+-cleaving enzymes (NADases) and the mammalian SARM1 (sterile alpha and TIR motif containing 1) NADase. We identify a variant of cyclic adenosine diphosphate ribose as a biomarker of TIR enzymatic activity. TIR enzymatic activity is induced by pathogen recognition and functions upstream of the genes enhanced disease susceptibility 1 (EDS1) and N requirement gene 1 (NRG1), which encode regulators required for TIR immune function. Thus, plant TIR-NLR receptors require NADase function to transduce recognition of pathogens into a cell death response.
DOI: 10.1126/science.aax1771
Source:https://science.sciencemag.org/content/365/6455/799
Science：《科學》，創刊於1880年。隸屬於美國科學促進會，最新IF：41.037