当前位置: X-MOL 学术Protein Sci. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Oligomerization of RIG-I and MDA5 2CARD domains.
Protein Science ( IF 8 ) Pub Date : 2019-11-07 , DOI: 10.1002/pro.3776
Cassie M Zerbe 1 , David J Mouser 1 , James L Cole 1, 2
Affiliation  

The innate immune system is the first line of defense against invading pathogens. The retinoic acid-inducible gene I (RIG-I) like receptors (RLRs), RIG-I and melanoma differentiation-associated protein 5 (MDA5), are critical for host recognition of viral RNAs. These receptors contain a pair of N-terminal tandem caspase activation and recruitment domains (2CARD), an SF2 helicase core domain, and a C-terminal regulatory domain. Upon RLR activation, 2CARD associates with the CARD domain of MAVS, leading to the oligomerization of MAVS, downstream signaling and interferon induction. Unanchored K63-linked polyubiquitin chains (polyUb) interacts with the 2CARD domain, and in the case of RIG-I, induce tetramer formation. However, the nature of the MDA5 2CARD signaling complex is not known. We have used sedimentation velocity analytical ultracentrifugation to compare MDA5 2CARD and RIG-I 2CARD binding to polyUb and to characterize the assembly of MDA5 2CARD oligomers in the absence of polyUb. Multi-signal sedimentation velocity analysis indicates that Ub4 binds to RIG-I 2CARD with a 3:4 stoichiometry and cooperatively induces formation of an RIG-I 2CARD tetramer. In contrast, Ub4 and Ub7 interact with MDA5 2CARD weakly and form complexes with 1:1 and 2:1 stoichiometries but do not induce 2CARD oligomerization. In the absence of polyUb, MDA5 2CARD self-associates to forms large oligomers in a concentration-dependent manner. Thus, RIG-I and MDA5 2CARD assembly processes are distinct. MDA5 2CARD concentration-dependent self-association, rather than polyUb binding, drives oligomerization and MDA5 2CARD forms oligomers larger than tetramer. We propose a mechanism where MDA5 2CARD oligomers, rather than a stable tetramer, function to nucleate MAVS polymerization.

中文翻译:

RIG-1和MDA5 2CARD域的低聚。

先天免疫系统是抵御病原体入侵的第一道防线。维甲酸诱导基因I(RIG-I)受体(RLRs),RIG-1和黑色素瘤分化相关蛋白5(MDA5)对于病毒RNA的宿主识别至关重要。这些受体包含一对N末端串联半胱天冬酶激活和募集结构域(2CARD),SF2解旋酶核心结构域和C末端调节结构域。在RLR激活后,2CARD与MAVS的CARD域结合,导致MAVS寡聚,下游信号传导和干扰素诱导。未锚定的K63连接的多聚泛素链(polyUb)与2CARD域相互作用,在RIG-1情况下,诱导四聚体形成。但是,MDA5 2CARD信号复合物的性质未知。我们已经使用沉降速度分析超速离心法比较了MDA5 2CARD和RIG-I 2CARD与polyUb的结合,并表征了在没有polyUb的情况下MDA5 2CARD低聚物的组装。多信号沉降速度分析表明,Ub4以3:4的化学计量比结合RIG-1 2CARD,并共同诱导RIG-1 2CARD四聚体的形成。相反,Ub4和Ub7与MDA5 2CARD相互作用较弱,并形成具有1:1和2:1化学计量比的复合物,但不会诱导2CARD寡聚。在不存在polyUb的情况下,MDA5 2CARD以浓度依赖的方式自缔合形成大的低聚物。因此,RIG-1和MDA5 2CARD组装过程是不同的。MDA5 2CARD浓度依赖性自我缔合,而不是polyUb结合,驱动低聚,MDA5 2CARD形成比四聚体更大的低聚物。我们提出了一种机制,其中MDA5 2CARD低聚物而不是稳定的四聚体起着核MAVS聚合作用的作用。
更新日期:2020-01-13
down
wechat
bug