Crystal structure of the TRIM25 B30.2 (PRYSPRY) domain: a key component of antiviral signalling.
Crystal structure of the TRIM25 B30.2 (PRYSPRY) domain: a key component of antiviral signalling.
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DOI：
10.1042/bj20121425
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发表时间：
2013-12-01
期刊：
影响因子：
--
通讯作者：
Nicholson SE
中科院分区：
文献类型：
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作者：
D'Cruz AA;Kershaw NJ;Chiang JJ;Wang MK;Nicola NA;Babon JJ;Gack MU;Nicholson SE
TRIM（三重基序）蛋白主要作为泛素E3连接酶起作用，其调节对感染的先天免疫应答。TRIM 25 [也称为Efp（雌激素反应指蛋白）]参与雌激素受体α信号传导的调节，并通过RIG-I（视黄酸诱导基因-I）参与先天免疫信号传导的调节。RIG-I感测胞质病毒RNA，随后在其N-末端CARD（半胱天冬酶募集结构域）处被TRIM 25泛素化，导致I型干扰素产生。与RIG-I的相互作用依赖于TRIM 25 B30.2结构域，这是一个由PRY和SPRY串联序列基序组成的蛋白质相互作用结构域。在本研究中，我们描述了TRIM 25 B30.2结构域的1.8 nm晶体结构，其表现出典型的B30.2/SPRY结构域折叠，包括两个N-末端α-螺旋，十三个β-链排列成两个β-片层和不同长度的环区域。与其他B30.2/SPRY结构的比较和对环区域的分析鉴定了推定的结合口袋，其可能参与结合靶蛋白。这得到了诱变和功能分析的支持，其鉴定了TRIM 25 B30.2结构域中的两个关键残基（Asp 488和Trp 621）对于结合RIG-I CARD是关键的。
TRIM (tripartite motif) proteins primarily function as ubiquitin E3 ligases that regulate the innate immune response to infection. TRIM25 [also known as Efp (oestrogen-responsive finger protein)] has been implicated in the regulation of oestrogen receptor α signalling and in the regulation of innate immune signalling via RIG-I (retinoic acid-inducible gene-I). RIG-I senses cytosolic viral RNA and is subsequently ubiquitinated by TRIM25 at its N-terminal CARDs (caspase recruitment domains), leading to type I interferon production. The interaction with RIG-I is dependent on the TRIM25 B30.2 domain, a protein-interaction domain composed of the PRY and SPRY tandem sequence motifs. In the present study we describe the 1.8 Å crystal structure of the TRIM25 B30.2 domain, which exhibits a typical B30.2/SPRY domain fold comprising two N-terminal α-helices, thirteen β-strands arranged into two β-sheets and loop regions of varying lengths. A comparison with other B30.2/SPRY structures and an analysis of the loop regions identified a putative binding pocket, which is likely to be involved in binding target proteins. This was supported by mutagenesis and functional analyses, which identified two key residues (Asp488 and Trp621) in the TRIM25 B30.2 domain as being critical for binding to the RIG-I CARDs.