On the three-finger protein domain fold and CD59-like proteins in Schistosoma mansoni.
On the three-finger protein domain fold and CD59-like proteins in Schistosoma mansoni.
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DOI：
10.1371/journal.pntd.0002482
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发表时间：
2013
影响因子：
3.8
通讯作者：
Leite LC
中科院分区：
文献类型：
--
作者：
Farias LP;Krautz-Peterson G;Tararam CA;Araujo-Montoya BO;Fraga TR;Rofatto HK;Silva FP Jr;Isaac L;Da'dara AA;Wilson RA;Shoemaker CB;Leite LC
据信，溶酶体通过在其表面上表达调节蛋白来逃避补体介导的杀伤。最近，人CD 59的六个同源物，补体系统膜攻击复合物的一个重要抑制剂，被确定在染色体基因组中。因此，重要的是研究这些分子是否可以作为CD 59样补体抑制剂的免疫逃避策略的一部分，在染色体。在这里，我们描述了7个假定SmCD 59样基因的分子特征，并试图解决两个亚型的假定生物学功能。hCD 59和hCD 59的三维结构的叠加分析显示，它们含有三指蛋白结构域（TFPD）。然而，在哺乳动物中参与补体识别的保守氨基酸残基不能被鉴定。实时荧光定量RT-PCR和Western blot分析表明，这些基因中的大多数在从自由生活的尾蚴到成虫阶段的过渡中上调。免疫定位实验和皮层制剂证实，至少有一些SmCD 59样蛋白的表面本地化，然而，显着的表达也检测到蠕虫的内部组织。最后，通过三种不同的方法评估两种SmCD 59蛋白在补体抑制中的参与：（i）使用在巴斯德毕赤酵母和E.大肠杆菌属;（ii）表达相应膜锚定蛋白的CHO细胞的补体抗性;和（iii）通过RNA干扰进行基因抑制后对血吸虫童虫的补体杀伤。我们的数据表明，这些蛋白质不参与补体激活的调节。我们的研究结果表明，这组蛋白属于TFPD超家族。它们的表达与宿主内阶段相关，存在于被膜表面，也存在于寄生虫内组织中。使用SmCD 59蛋白抑制补体的三种不同方法强烈表明，这些蛋白不是补体抑制剂，它们在溶酶体中的功能仍有待确定。血吸虫是在血流中驻留多年的寄生虫，需要有效的机制来逃避免疫应答效应物，如补体沉积。一组类似于人CD 59的基因，在哺乳动物中的一个重要的补体抑制剂，被确定在染色体基因组中。蛋白质结构的计算机预测表明，染色体蛋白和哺乳动物CD 59蛋白家族的实质相似性，由于它们的三指形空间构象，它们是三指蛋白结构域折叠超家族（TFPD）的成员。该家族的蛋白质的成员也被证明是主要表达在哺乳动物阶段，当蠕虫暴露于补体，并发现存在于宿主相互作用的表面的蛋白体。采用三种不同的方法来测试这些蛋白质在补体抑制中的可能参与。我们的研究结果强烈表明，这些蛋白质不参与抑制补体，需要进一步的研究，以建立其功能的作用。
It is believed that schistosomes evade complement-mediated killing by expressing regulatory proteins on their surface. Recently, six homologues of human CD59, an important inhibitor of the complement system membrane attack complex, were identified in the schistosome genome. Therefore, it is important to investigate whether these molecules could act as CD59-like complement inhibitors in schistosomes as part of an immune evasion strategy. Herein, we describe the molecular characterization of seven putative SmCD59-like genes and attempt to address the putative biological function of two isoforms. Superimposition analysis of the 3D structure of hCD59 and schistosome sequences revealed that they contain the three-fingered protein domain (TFPD). However, the conserved amino acid residues involved in complement recognition in mammals could not be identified. Real-time RT-PCR and Western blot analysis determined that most of these genes are up-regulated in the transition from free-living cercaria to adult worm stage. Immunolocalization experiments and tegument preparations confirm that at least some of the SmCD59-like proteins are surface-localized; however, significant expression was also detected in internal tissues of adult worms. Finally, the involvement of two SmCD59 proteins in complement inhibition was evaluated by three different approaches: (i) a hemolytic assay using recombinant soluble forms expressed in Pichia pastoris and E. coli; (ii) complement-resistance of CHO cells expressing the respective membrane-anchored proteins; and (iii) the complement killing of schistosomula after gene suppression by RNAi. Our data indicated that these proteins are not involved in the regulation of complement activation. Our results suggest that this group of proteins belongs to the TFPD superfamily. Their expression is associated to intra-host stages, present in the tegument surface, and also in intra-parasite tissues. Three distinct approaches using SmCD59 proteins to inhibit complement strongly suggested that these proteins are not complement inhibitors and their function in schistosomes remains to be determined. Schistosomes are parasites that reside for many years in the blood stream, demanding efficient mechanisms of evading immune response effectors such as complement deposition. A group of genes similar to human CD59, an important complement inhibitor in mammals, were identified in the schistosome genome. Computer predictions of protein structure indicated substantial similarity of the schistosome proteins and the mammalian CD59 family of proteins, which due to their three-finger-shaped spatial conformation are members of the Three-Finger Protein Domain fold superfamily (TFPD). Members of this family of schistosome proteins were also shown to be expressed predominantly during the mammalian stages when worms are exposed to complement and found to be present at the host-interactive surface of schistosomes. Three different methods were employed to test the possible involvement of these proteins in complement inhibition. Our results strongly suggest that these proteins are not involved in the inhibition of complement and that further studies are needed to establish their functional role(s) in schistosomes.
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影响因子：
2
作者：
Farias, Leonardo P.;Tararam, Cibele A.;de Cerqueira Leite, Luciana Cezar
通讯作者：
de Cerqueira Leite, Luciana Cezar
影响因子：
3.8
作者：
Farias, Leonardo Paiva;Rodrigues, Dunia;Leite, Luciana C. C.
通讯作者：
Leite, Luciana C. C.
DOI：
10.1111/j.1574-695x.2001.tb00521.x
发表时间：
2001-10-01
影响因子：
--
作者：
Huang, J;Gou, DM;Cai, CC
通讯作者：
Cai, CC
影响因子：
4.8
作者：
Krautz-Peterson, Greice;Camargo, Simone;Skelly, Patrick J.
通讯作者：
Skelly, Patrick J.
影响因子：
5.4
作者：
Galat, Andrzej;Gross, Gregory;Menez, Andre
通讯作者：
Menez, Andre