Trypanosoma brucei brucei: endocytic recycling is important for mouse infectivity.
Trypanosoma brucei brucei: endocytic recycling is important for mouse infectivity.
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DOI：
10.1016/j.exppara.2011.01.001
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发表时间：
2011-04
影响因子：
2.1
通讯作者：
Field, Mark C.
中科院分区：
文献类型：
--
作者：
Natesan, Senthil Kumar A.;Black, Alana;Matthews, Keith R.;Mottram, Jeremy C.;Field, Mark C.
锥虫通过抗原变异逃避免疫反应。锥虫还通过内吞作用将免疫效应物从表面清除。部分缺陷的内吞摄取并不影响小鼠的感染性。►循环通路缺陷确实会降低小鼠的传染性。非洲锥虫布鲁氏锥虫的内吞作用与维持细胞表面蛋白质组的稳态、鞭毛袋的形态密切相关，最近被证明是一个真正的药物靶点。rnai介导的内吞运输所需的许多因子的敲低，包括几个小的gtp酶，主要的外壳蛋白网格蛋白和网格蛋白相关受体epsinR，导致体外细胞快速死亡。体外生存能力的迅速丧失阻碍了RNAi对体内锥虫内吞作用的有意义的研究。在这里，我们试图通过对内吞系统产生比完全功能消融更温和的影响的策略来解决这个问题。我们创建了一个锥虫网格蛋白重链半合子和几个表达Rab5和Rab11突变形式的系，如前所述。所有在体外培养中都是可行的，对增殖率或细胞周期的影响可以忽略不计。网格蛋白半合子表达的网格蛋白重链在野生型水平的50%左右，但尽管如此，在小鼠中没有表现出生长缺陷，而Rab5突变体在体内没有影响增殖，尽管有明确的证据表明其对内噬作用有影响。相比之下，我们发现表达一个显性活性Rab11突变体导致小鼠生长受损。这些数据表明，锥虫可能耐受网格蛋白表达部分减少和早期内吞作用改变的影响，但对该途径的再循环臂的改变更敏感。
► Trypanosomes evade the immune response by antigenic variation. ► Trypanosomes also remove immune effectors from the surface by endocytosis. ► Partially defective endocytic uptake does not compromise mouse infectivity. ► Recycling pathway defects do compromise mouse infectivity. Endocytosis in the African trypanosome, Trypanosoma brucei, is intimately involved in maintaining homeostasis of the cell surface proteome, morphology of the flagellar pocket and has recently been demonstrated as a bona fide drug target. RNAi-mediated knockdown of many factors required for endocytic transport, including several small GTPases, the major coat protein clathrin and a clathrin-associated receptor, epsinR, results in rapid cell death in vitro. Rapid loss of viability in vitro precludes meaningful investigation by RNAi of the roles of trypanosome endocytosis in vivo. Here we have sought to address this issue using strategies designed to produce milder effects on the endocytic system than complete functional ablation. We created a trypanosome clathrin heavy chain hemizygote and several lines expressing mutant forms of Rab5 and Rab11, described previously. All are viable in in vitro culture, with negligible impact to proliferative rates or cell cycle. Clathrin hemizygotes express clathrin heavy chain at ∼50% of wild type levels, but despite this demonstrate no defect to growth in mice, while none of the Rab5 mutants affected proliferation in vivo, despite clear evidence for effects on endocytosis. By contrast we find that expressing a dominantly active Rab11 mutant led to compromised growth in mice. These data indicate that trypanosomes likely tolerate the effects of partly decreased clathrin expression and alterations in early endocytosis, but are more sensitive to alterations in the recycling arm of the pathway.
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影响因子：
4.4
作者：
Koumandou VL;Natesan SK;Sergeenko T;Field MC
通讯作者：
Field MC
影响因子：
64.5
作者：
Engstler, Markus;Pfohl, Thomas;Overath, Peter
通讯作者：
Overath, Peter
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4.8
作者：
Hall, BS;Pal, A;Field, MC
通讯作者：
Field, MC
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作者：
O'Brien, Theresa C.;Mackey, Zachary B.;McKerrow, James H.
通讯作者：
McKerrow, James H.
影响因子：
4.5
作者：
Chung, Wei-Lian;Leung, Ka Fai;Field, Mark C.
通讯作者：
Field, Mark C.