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研究揭示植物免疫受体功能发挥机制
作者:小柯机器人 发布时间:2019/8/23 13:56:51

近日,美国科罗拉多州立大学、北卡罗来纳大学和华盛顿大学的研究人员合作取得一项新进展。他们发现植物免疫受体的TIR结构域是促进细胞死亡的NAD+裂解酶。该项研究成果发表在2019年8月23日出版的《科学》上。

研究人员证明NLR的植物Toll /白细胞介素-1受体(TIR)结构域是能够以其氧化形式(NAD+)降解烟酰胺腺嘌呤二核苷酸的酶。植物TIR结构域的细胞死亡诱导和NAD+切割活性都需要已知的自结合界面和假定的催化谷氨酸,这个位点在细菌TIR NAD +切割酶(NADases)和哺乳动物SARM1(sterile alpha and TIR motif containing 1)中都是保守的。研究人员鉴定到一个环磷酸二磷酸核糖的变体可作为TIR酶活性的生物标志物。TIR酶活性由病原体识别所诱导,并在EDS1(enhanced disease susceptibility 1)和NRG1(N requirement gene 1)的上游发挥功能,这两个基因编码TIR免疫功能所需的调节蛋白。因此,植物TIR-NLR受体需要NADase功能来将病原体识别转化为细胞死亡反应。

据了解,植物NLR(nucleotide-binding leucine-rich repeat)免疫受体通过未知机制激活细胞死亡并赋予疾病抗性。

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

期刊信息
Science:《科学》,创刊于1880年。隶属于美国科学促进会,最新IF:41.037