Structure-function analysis of the Anopheles gambiae LRIM1/APL1C complex and its interaction with complement C3-like protein TEP1.
Structure-function analysis of the Anopheles gambiae LRIM1/APL1C complex and its interaction with complement C3-like protein TEP1.
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DOI：
10.1371/journal.ppat.1002023
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发表时间：
2011-04
期刊：
影响因子：
6.7
通讯作者：
Christophides GK
中科院分区：
文献类型：
--
作者：
Povelones M;Upton LM;Sala KA;Christophides GK
疟疾威胁着世界一半人口，造成毁灭性的人员伤亡。非洲主要的疟疾病媒冈比亚按蚊编码最近发现的富含亮氨酸重复蛋白家族的 24 个成员，该蛋白家族名为 LRIM。该家族的两个成员 LRIM1 和 APL1C 是蚊子补体样途径的重要组成部分，对于疟原虫寄生虫的免疫防御非常重要。 LRIM1 和 APL1C 仅作为二硫键复合物在血淋巴中循环，与补体 C3 样蛋白 TEP1 的成熟形式特异性相互作用。我们研究了 LRIM1/APL1C 复合物形成的特异性以及这些蛋白质的哪些区域需要与 TEP1 相互作用。为了解决这些问题，我们生成了一组改变关键保守结构元件的 LRIM1 和 APL1C 等位基因，并在细胞培养物中分析它们的复杂形成以及与 TEP1 的相互作用。我们的数据表明，异质复合物形成是 LRIM1 和 APL1C 的固有能力，并识别形成分子间二硫键的关键同源半胱氨酸残基。我们还证明卷曲螺旋结构域是 TEP1 的结合位点，但也有助于 LRIM1/APL1C 复合物形成的特异性。此外，我们还发现 LRIM1/APL1C 复合物与其他三种 TEP 蛋白的成熟形式相互作用，其中一种 TEP3，我们已将其定性为疟原虫拮抗剂。我们得出结论，LRIM1 和 APL1C 包含三个不同的模块：C 端卷曲螺旋结构域，可以携带不同的 TEP 蛋白货物，可能具有不同的功能；控制复合物形成的中央富含半胱氨酸的区域；以及 N 端富含亮氨酸的重复区域，在病原体识别中具有假定的作用。传播疟疾的蚊子冈比亚按蚊利用类似补体的途径来防御疟原虫寄生虫。补体 C3 样蛋白 TEP1 与入侵寄生虫的表面结合，引发其破坏和清除。 LRIM1 和 APL1C 是两种富含亮氨酸的重复蛋白，形成二硫键复合物，可稳定成熟的 TEP1 并促进其与寄生虫的结合。在这里，我们研究了 LRIM1/APL1C 复合物的结构和生化特征及其与 TEP1 的相互作用。我们确定了负责共价连接 LRIM1 和 APL1C 的关键氨基酸残基以及 TEP1 结合的复合物区域。重要的是，我们证明 LRIM1/APL1C 复合物可以与其他三种 TEP 的成熟形式相互作用，其中包括 TEP3，我们将其定性为新型疟原虫拮抗剂。我们的结果表明 LRIM1/APL1C 复合物具有模块化架构，其中不同的功能映射到不同的区域。我们的研究提供了关于冈比亚疟原虫补体途径如何帮助蚊子对抗疟疾寄生虫的重要见解。
Malaria threatens half the world's population and exacts a devastating human toll. The principal malaria vector in Africa, the mosquito Anopheles gambiae, encodes 24 members of a recently identified family of leucine-rich repeat proteins named LRIMs. Two members of this family, LRIM1 and APL1C, are crucial components of the mosquito complement-like pathway that is important for immune defense against Plasmodium parasites. LRIM1 and APL1C circulate in the hemolymph exclusively as a disulfide-bonded complex that specifically interacts with the mature form of the complement C3-like protein, TEP1. We have investigated the specificity of LRIM1/APL1C complex formation and which regions of these proteins are required for interactions with TEP1. To address these questions, we have generated a set of LRIM1 and APL1C alleles altering key conserved structural elements and assayed them in cell culture for complex formation and interaction with TEP1. Our data indicate that heterocomplex formation is an intrinsic ability of LRIM1 and APL1C and identify key homologous cysteine residues forming the intermolecular disulfide bond. We also demonstrate that the coiled-coil domain is the binding site for TEP1 but also contributes to the specificity of LRIM1/APL1C complex formation. In addition, we show that the LRIM1/APL1C complex interacts with the mature forms of three other TEP proteins, one of which, TEP3, we have characterized as a Plasmodium antagonist. We conclude that LRIM1 and APL1C contain three distinct modules: a C-terminal coiled-coil domain that can carry different TEP protein cargoes, potentially with distinct functions, a central cysteine-rich region that controls complex formation and an N-terminal leucine-rich repeat with a putative role in pathogen recognition. The malaria-transmitting mosquito, Anopheles gambiae, uses a complement-like pathway to defend against Plasmodium parasites. The complement C3-like protein, TEP1, binds to the surface of invading parasites, triggering their destruction and clearance. LRIM1 and APL1C, two leucine-rich repeat proteins, form a disulfide-bonded complex which stabilizes mature TEP1 and promotes its binding to parasites. Here, we investigate the structural and biochemical features of the LRIM1/APL1C complex and its interaction with TEP1. We identify key amino acid residues responsible for covalently linking LRIM1 and APL1C and the region of the complex where TEP1 binds. Importantly, we demonstrate that the LRIM1/APL1C complex can interact with the mature form of three other TEPs, including TEP3, which we characterize as a novel Plasmodium antagonist. Our results suggest that the LRIM1/APL1C complex has a modular architecture in which distinct functions map to different regions. Our study provides important insights into how the A. gambiae complement pathway helps mosquitoes fight against the malaria parasite.
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影响因子：
6.7
作者：
Habtewold T;Povelones M;Blagborough AM;Christophides GK
通讯作者：
Christophides GK
影响因子：
6.7
作者：
Mitri C;Jacques JC;Thiery I;Riehle MM;Xu J;Bischoff E;Morlais I;Nsango SE;Vernick KD;Bourgouin C
通讯作者：
Bourgouin C
影响因子：
6.7
作者：
Dong Y;Aguilar R;Xi Z;Warr E;Mongin E;Dimopoulos G
通讯作者：
Dimopoulos G
影响因子：
64.8
作者：
Pancer, Z;Amemiya, CT;Cooper, MD
通讯作者：
Cooper, MD
DOI：
10.1016/s1357-2725(02)00280-7
发表时间：
2003-08-01
影响因子：
4
作者：
Andrews, RK;Gardiner, EE;Berndt, MC
通讯作者：
Berndt, MC