RECEPTORS FOR THE HOST LOW-DENSITY LIPOPROTEINS ON THE HEMOFLAGELLATE TRYPANOSOMA-BRUCEI - PURIFICATION AND INVOLVEMENT IN THE GROWTH OF THE PARASITE
RECEPTORS FOR THE HOST LOW-DENSITY LIPOPROTEINS ON THE HEMOFLAGELLATE TRYPANOSOMA-BRUCEI - PURIFICATION AND INVOLVEMENT IN THE GROWTH OF THE PARASITE
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DOI：
10.1073/pnas.85.18.6753
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发表时间：
1988-09-01
影响因子：
11.1
通讯作者：
COURTOY, PJ
中科院分区：
文献类型：
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作者：
COPPENS, I;BAUDHUIN, P;COURTOY, PJ
细长血流形式的布氏锥虫显示受体介导的内吞宿主的低密度脂蛋白（LDL）颗粒。我们将该种LDL受体纯化至接近均一（约1000倍纯化），并获得了抗该受体的单特异性多克隆抗体，经NaDodSO_4/聚丙烯酰胺凝胶电泳分析，纯化的受体由一个亚基组成，表观分子量为86 kDa。其等电点为5.9。平均而言，每个细胞暴露52，000个拷贝的低亲和力受体（Kd为250 nM）和1800个拷贝的高亲和力受体（Kd为5.7 nM）。根据固定寄生虫的间接整块免疫标记，受体apepars被定位于鞭毛口袋膜和鞭毛膜，并从细胞周膜的其余部分完全缺席。锥虫在体外的最佳生长需要LDL：细胞生长可以通过从培养基中去除LDL或通过针对纯化的LDL受体的抗体来抑制。在这两种情况下，生长都受到过量LDL的抑制。
The slender bloodstream form of Trypanosoma brucei shows receptor-mediated endocytosis of low density lipoprotein (LDL) particles of its hosts. We have purified the LDL receptor of this species nearly to homogeneity (about 1000-fold purification) and obtained monospecific polyclonal antibodies against it. As analyzed by NaDodSO4/polyacrylamide gel electrophoresis, the purified receptor consists of a single subunit, with an apparent molecular mass of 86 kDa. Its isoelectric point is 5.9. On the average, each cell exposes 52,000 copies of low-affinity receptors (Kd of 250 nM) and 1800 copies of high-affinity receptors (Kd of 5.7 nM). According to indirect en bloc immunolabeling of fixed parasites, the receptor apepars to be localized to the flagellar pocket membrane and the flagellar membrane and to be completely absent from the rest of the pericellular membrane. LDL is required for optimal growth of the trypanosome in vitro: cell growth can be inhibited either by removal of LDL from the culture medium or by antibodies against the purified LDL receptors. In both cases, growth is restroed by the addition of excess LDL.