Data from: The NBS-LRR architectures of plant R-proteins and metazoan NLRs evolved in independent events

There are intriguing parallels between plants and animals, with respect to the structures of their innate immune receptors, that suggest universal principles of innate immunity. The cytosolic nucleotide binding site–leucine rich repeat (NBS-LRR) resistance proteins of plants (R-proteins) and the so-called NOD-like receptors of animals (NLRs) share a domain architecture that includes a STAND (signal transduction ATPases with numerous domains) family NTPase followed by a series of LRRs, suggesting inheritance from a common ancestor with that architecture. Focusing on the STAND NTPases of plant R-proteins, animal NLRs, and their homologs that represent the NB-ARC (nucleotide-binding adaptor shared by APAF-1, certain R gene products and CED-4) and NACHT (named for NAIP, CIIA, HET-E, and TEP1) subfamilies of the STAND NTPases, we analyzed the phylogenetic distribution of the NBS-LRR domain architecture, used maximum-likelihood methods to infer a phylogeny of the NTPase domains of R-proteins, and reconstructed the domain structure of the protein containing the common ancestor of the STAND NTPase domain of R-proteins and NLRs. Our analyses reject monophyly of plant R-proteins and NLRs and suggest that the protein containing the last common ancestor of the STAND NTPases of plant R-proteins and animal NLRs (and, by extension, all NB-ARC and NACHT domains) possessed a domain structure that included a STAND NTPase paired with a series of tetratricopeptide repeats. These analyses reject the hypothesis that the domain architecture of R-proteins and NLRs was inherited from a common ancestor and instead suggest the domain architecture evolved at least twice. It remains unclear whether the NBS-LRR architectures were innovations of plants and animals themselves or were acquired by one or both lineages through horizontal gene transfer.植物与动物在先天免疫受体的结构层面存在引人入胜的相似性，这暗示了先天免疫的通用原则。植物的胞质核苷酸结合位点-亮氨酸重复序列（nucleotide binding site–leucine rich repeat, NBS-LRR）抗性蛋白（简称R蛋白）与动物的所谓核苷酸结合寡聚化结构域样受体（NOD-like receptors, NLRs）共享一套域架构：即包含一个STAND（signal transduction ATPases with numerous domains，多结构域信号转导ATP酶）家族核苷三磷酸酶（nucleoside triphosphatase, NTPase），其后串联一系列亮氨酸重复序列，这提示二者源自具有该域架构的共同祖先。我们聚焦于植物R蛋白、动物NLRs及其同源物的STAND核苷三磷酸酶，这类酶属于STAND核苷三磷酸酶的NB-ARC（APAF-1、部分R基因产物与CED-4共有的核苷酸结合适配域）与NACHT（取自NAIP、CIIA、HET-E与TEP1首字母命名）亚家族，分析了NBS-LRR域架构的系统发育分布，采用最大似然法推导了R蛋白核苷三磷酸酶域的系统发育树，并重构了包含植物R蛋白与NLRs的STAND核苷三磷酸酶域共同祖先的蛋白质域结构。我们的分析结果否定了植物R蛋白与NLRs的单系起源假说，并提出：植物R蛋白与动物NLRs（进而涵盖所有NB-ARC与NACHT域）的STAND核苷三磷酸酶的最近共同祖先所携带的蛋白质域结构，包含一个STAND核苷三磷酸酶与串联的四肽重复序列（tetratricopeptide repeats, TPRs）。这些分析推翻了"R蛋白与NLRs的域架构源自共同祖先"的假说，转而表明该域架构至少独立演化过两次。目前仍不清楚NBS-LRR域架构是动植物自身的创新，还是二者之一或二者通过水平基因转移获得的外来性状。