Toxoplasma gondii Hsp20 is a stripe-arranged chaperone-like protein associated with the outer leaflet of the inner membrane complex.
Toxoplasma gondii Hsp20 is a stripe-arranged chaperone-like protein associated with the outer leaflet of the inner membrane complex.
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DOI：
10.1042/bc20080004
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发表时间：
2008-08
影响因子：
2.7
通讯作者：
Angel SO
中科院分区：
文献类型：
--
作者：
de Miguel N;Lebrun M;Heaslip A;Hu K;Beckers CJ;Matrajt M;Dubremetz JF;Angel SO
弓形虫是最成功的寄生虫之一，近一半的人口受到慢性感染。弓形虫有五个 sHsps [小 Hsps（热休克蛋白）]，位于不同的亚细胞区室中。其中，Hsp20显示位于寄生虫体的外围。小热休克蛋白分布广泛，是保守性最差的分子伴侣家族。膜结构中小热激蛋白的存在是不寻常的。使用高分辨率荧光显微镜和电子显微镜进一步分析了 Hsp20 的定位，结果表明 Hsp20 与 IMC（内膜复合物）的外表面相关，呈一组不连续条纹，遵循与膜下微管相同的螺旋轨迹。 Hsp20 的去垢剂提取谱与 GAP45 [45 kDa GAP（滑动相关蛋白）]（一种与 IMC 相关的滑胶体蛋白）类似，但与 IMC1 蛋白的去垢剂提取谱不同。尽管我们无法在正常或应激速殖子中检测到 Hsp20 的相互作用蛋白伴侣，但可以观察到 Hsp20 与磷脂酰肌醇 4-磷酸和磷脂酰肌醇 4,5-二磷酸磷脂的相互作用。 Hsp20 被证明与寄生虫的特殊膜结构 IMC 相关。这种不连续的条纹排列在弓形虫中是独一无二的，表明 IMC 外叶的拓扑结构并不均匀。
Toxoplasma gondii is among the most successful parasites, with nearly half of the human population chronically infected. T. gondii has five sHsps [small Hsps (heat-shock proteins)] located in different subcellular compartments. Among them, Hsp20 showed to be localized at the periphery of the parasite body. sHsps are widespread, constituting the most poorly conserved family of molecular chaperones. The presence of sHsps in membrane structures is unusual. The localization of Hsp20 was further analysed using high-resolution fluorescent light microscopy as well as electron microscopy, which revealed that Hsp20 is associated with the outer surface of the IMC (inner membrane complex), in a set of discontinuous stripes following the same spiralling trajectories as the subpellicular microtubules. The detergent extraction profile of Hsp20 was similar to that of GAP45 [45 kDa GAP (gliding-associated protein)], a glideosome protein associated with the IMC, but was different from that of IMC1 protein. Although we were unable to detect interacting protein partners of Hsp20 either in normal or stressed tachyzoites, an interaction of Hsp20 with phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate phospholipids could be observed. Hsp20 was shown to be associated with a specialized membranous structure of the parasite, the IMC. This discontinuous striped-arrangement is unique in T. gondii, indicating that the topology of the outer leaflet of the IMC is not homogeneous.