Low pH facilitates uptake of proteins by cells through a non-endocytic pathway.
Low pH facilitates uptake of proteins by cells through a non-endocytic pathway.
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DOI：
10.1093/jb/mvh087
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发表时间：
2004-06
影响因子：
2.7
通讯作者：
M. Motizuki;T. Takei;K. Tasaka;S. Yokota;S. Kojima;T. Haga;K. Tsurugi
中科院分区：
文献类型：
--
作者：
M. Motizuki;T. Takei;K. Tasaka;S. Yokota;S. Kojima;T. Haga;K. Tsurugi
我们之前注意到牛载脂蛋白 A-II (apoA-II) 具有杀菌作用，导致细胞质形态发生变化。为了确定具有酸性等电点 (pIs) 的 apoA-II 和 apoA-I 是否以及如何进入细胞，我们测定了成纤维细胞对 FITC 标记蛋白的摄取率，发现在抑制内吞作用的条件下，它们在低 pH 值比中性 pH 值更容易进入细胞。尽管不同蛋白质的摄取效率有所不同，但无论分子量 (M(r)) 或 pI 为何，低 pH 条件下蛋白质的摄取均呈时间依赖性增强。此外，pH 梯度被证明是易位的主要驱动力。由于细胞在 4°C 下 pH 值高于 4 时可存活 2 小时，并且内化 β-半乳糖苷酶在这些条件下具有活性，因此我们建议该程序适用于将蛋白质注射到细胞中，而无需使用显微注射器等设备。
We previously noted that bovine apolipoprotein A-II (apoA-II) had a bactericidal effect causing morphological changes in the cytoplasm. To determine whether and how apoA-II and apoA-I, which have acidic isoelectric points (pIs), enter cells, we determined the rates of uptake of FITC-labeled proteins by fibroblast cells and found that they entered cells more easily at low pH than at neutral pH under conditions where endocytosis was inhibited. The enhanced uptake of proteins at low pH was also observed for other proteins examined regardless of the molecular weight (M(r)) or pI in a time-dependent manner, although the efficiency of uptake varied among the proteins. Furthermore, a pH gradient was shown to be the main driving force for the translocation. As cells were viable above pH 4 for 2 h at 4 degrees C and internalized beta-galactosidase was active under these conditions, we suggest that this procedure is applicable to the injection of proteins into cells without the use of an apparatus such as a microinjector.