NLRP10蛋白的结构和自组装

Structure and Self-assembly of NLRP10

NLRP10是NOD样受体(NOD-like receptor,NLR)蛋白家族的特殊成员,它具有N端热蛋白结构域(pyrin-like domain,PYD)和中间的核苷酸结合寡聚结构域(nucleotide-binding and oligomerization domain,NOD),却不具有亮氨酸富集重复结构域(leucine-rich repeat domain,LRR),这表明NLRP10可能并不直接参与病原微生物的识别,而是行使免疫调节的功能.研究表明,NLRP10能促进NOD1介导的免疫反应,也能抑制NLRP3炎症小体的激活.在参与免疫调控时,NLRP10以聚集体的形式与接头蛋白ASC结合,继而招募相应免疫信号通路中的其他成员.NLRP10蛋白在结构方面的研究很有限,目前仅有PYD结构域的相关报道.本文在尝试纯化全长人源NLRP10时,同时得到了PYD结构域缺失的稳定蛋白片段,电镜结果表明存在条形和环形两种形态的聚集体.通过序列分析和定点突变,我们找到了潜在的蛋白质降解位点,从而解决了纯化过程中蛋白质降解的问题,为后期的高分辨结构测定奠定了基础.

NLRP10 is a special member of NOD-like receptors （NLRs） family that lacks the leucine-rich repeats, suggesting that NLRP10 may act as an immunity regulator rather than directly receptor recognizing intracellular pathogen products. Previous studies on NLRP10 show that NLRP10 can interact with several components of NOD1 pathway thereby enhancing NOD1-mediated innate immune responses. In particular models, NLRP10 also negatively affects the activation of NLRP3 inflammasome. It has been proposed that NLRP10 oligomers interact with ASC to form a multi-protein platform for the recruitment of caspase-1 or other signaling components. Here, we show that pyrin-like domain （PYD） degradation induce the formation of NLRP10 oligomers, which present stick-shaped and circular structure. With the NLRP10 mutant G173A made by means of site-directed mutagenesis, we successfully obtain homogeneous full-length NLRP10 preparations. Corresponding gel filtration analysis and electron microscope （EM） data further proved that the PYD domain is important in protecting NLRP10 against aggregation.