Syntaxin 16 and syntaxin 5 are required for efficient retrograde transport of several exogenous and endogenous cargo proteins.
Syntaxin 16 and syntaxin 5 are required for efficient retrograde transport of several exogenous and endogenous cargo proteins.
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语法16和语法5是有效地逆行几种外源和内源性货物蛋白的逆行运输所必需的。
DOI：
10.1242/jcs.03436
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发表时间：
2007-04-15
影响因子：
4
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中科院分区：
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逆行转运允许蛋白质和脂质离开内吞途径到达其他细胞内区室，如TGN/高尔基体膜、内质网，以及在某些情况下到达胞质溶胶。在这里，我们使用RNA干扰SNARE蛋白syntaxin 5和syntaxin 16，结合最近开发的定量运输分析，形态学方法和细胞中毒分析，表明这些SNARE蛋白不仅是滋贺毒素有效逆行转运所需的，而且也是内源性货物蛋白甘露糖6-磷酸受体，以及用于将霍乱毒素和蓖麻毒素生产性地运输到细胞中。我们已经发现，syntaxin 16的功能是专门需要的，并限于逆行途径。引人注目的是，突触融合蛋白5 RNA干扰保护细胞特别强烈地抵抗滋贺毒素。由于我们的运输分析表明，除了抑制逆行内体到TGN的运输外，syntaxin 5的沉默对滋贺毒素的内吞作用或从TGN/高尔基体膜到内质网的运输没有额外的影响，我们假设syntaxin 5也具有不依赖于运输的功能。总之，我们的数据表明，几种细胞和外源货物蛋白使用相同的陷阱机制的元素，早期/再循环内体和TGN/高尔基体膜之间的有效逆行转运。
Retrograde transport allows proteins and lipids to leave the endocytic pathway to reach other intracellular compartments, such as TGN/Golgi membranes, the endoplasmic reticulum, and in some instances, the cytosol. Here, we have used RNA interference against the SNARE proteins syntaxin 5 and syntaxin 16 combined with recently developed quantitative trafficking assays, morphological approaches, and cell intoxication analysis to show that these SNARE proteins are not only required for efficient retrograde transport of Shiga toxin, but also for that of an endogenous cargo protein, the mannose 6-phosphate receptor, and for the productive trafficking into cells of cholera toxin and ricin. We have found that the function of syntaxin 16 was specifically required for, and restricted to the retrograde pathway. Strikingly, syntaxin 5 RNA interference protected cells particularly strongly against Shiga toxin. Since our trafficking analysis showed that apart from inhibiting retrograde endosomes-to-TGN transport, the silencing of syntaxin 5 had no additional effect on Shiga toxin endocytosis or trafficking from TGN/Golgi membranes to the endoplasmic reticulum, we hypothesize that syntaxin 5 also has trafficking-independent functions. In summary, our data demonstrate that several cellular and exogenous cargo proteins use elements of the same SNARE machinery for efficient retrograde transport between early/recycling endosomes and TGN/Golgi membranes.