Macrophage damage by Leishmania amazonensis cytolysin:: Evidence of pore formation on cell membrane
Macrophage damage by Leishmania amazonensis cytolysin:: Evidence of pore formation on cell membrane
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DOI：
10.1128/iai.68.8.4578-4584.2000
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发表时间：
2000-08-01
影响因子：
3.1
通讯作者：
Horta, MF
中科院分区：
文献类型：
--
作者：
Noronha, FSM;Cruz, JS;Horta, MF
我们之前的研究表明，亚马逊利什曼原虫的原鞭毛体和无鞭毛体都含有一种裂解蛋白，可以破坏红细胞和有核细胞，包括巨噬细胞（f.s.m. Noronha, f.j. Ramalho-Pinto，和m.f. Horta，感染）。免疫学。64:3975-3982,1996)。使用膜片钳技术，我们在这里表明，寄生虫提取物的细胞损伤是通过在靶膜上形成非选择性孔介导的。这表明亚马逊乳杆菌胞溶素是一种成孔蛋白（PFP），这里称为leishporin。我们发现，寄生虫提取物形成的孔直径是不均匀的，根据细胞溶素浓度或时间的不同，直径从1.6 nm到bbb6.1 nm不等。我们还表明，孔的形成涉及到PFP与靶细胞膜的结合，这是一个与温度无关的事件，是必要的，但不足以裂解细胞。接下来是一个与温度相关的步骤，触发裂解，可能是脂质双分子层中蛋白质亚基的插入和聚合。我们提供的证据表明，单一亚基的聚合必须发生孔隙的形成。此外，我们还发现亚马逊乳杆菌表达的分子与其他PFPs具有抗原性同源性。
We have previously shown that both promastigotes and amastigotes of Leishmania amazonensis contain a lytic protein that damages erythrocytes and nucleated cells, including macrophages (F. S. M. Noronha, F. J. Ramalho-Pinto, and M. F. Horta, Infect. Immun. 64:3975-3982, 1996). Using the patch-clamp technique, we show here that cell damage by parasite extracts is mediated by the formation of nonselective pores on the target membrane. This demonstrates that L. amazonensis cytolysin is a pore-forming protein (PFP), here named leishporin. We show that the diameters of the pores formed by parasite extracts are heterogeneous, varying from similar to 1.6 to >6.1 nm according to cytolysin concentration or time. We also show that pore formation involves the binding of the PFP to the target cell membrane, a temperature-independent event that is necessary but not sufficient to lyse cells. This is followed by a temperature-dependent step that triggers lysis, probably the insertion and the polymerization of protein subunits in the lipid bilayer. We provide evidence that suggests that polymerization of single subunits must occur for pore formation. We show, in addition, that L. amazonensis expresses molecules antigenically homologous to other PFPs.