Primaquine interferes with membrane recycling from endosomes to the plasma membrane through a direct interaction with endosomes which does not involve neutralisation of endosomal pH nor osmotic swelling of endosomes
Primaquine interferes with membrane recycling from endosomes to the plasma membrane through a direct interaction with endosomes which does not involve neutralisation of endosomal pH nor osmotic swelling of endosomes
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DOI：
10.1078/0171-9335-00062
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发表时间：
2000-06-01
影响因子：
6.6
通讯作者：
Stoorvogel, W
中科院分区：
文献类型：
--
作者：
van Weert, AWM;Geuze, HJ;Stoorvogel, W
抗疟疾药物伯氨喹是一种弱碱，其以质子化形式在内体中积累，从而中和内体pH，巴弗洛霉素Al通过抑制液泡质子泵来防止内体酸化。虽然这两种药物都能中和内体pH值，但只有伯氨喹对内吞蛋白质再循环至质膜具有强烈的抑制作用（货车Weert等，（1995），J，Cell Biol，130，821-834）。这表明伯氨喹干扰除了内体pH之外的参数，该参数对于膜再循环是必需的。在0.3mM伯氨喹存在下，内吞的转铁蛋白受体在细胞内积累，但在另外存在巴夫洛霉素A1的情况下不积累。因此，在相对低的浓度下，需要质子泵驱动的伯氨喹在内体中的积累来抑制膜再循环，这表明伯氨喹的靶与内体相关，1 mM伯氨喹对转铁蛋白受体再循环的抑制作用不被另外存在的巴夫洛霉素A1逆转，表明由于质子化伯氨喹的积累引起的内体的渗透膨胀也不能解释其作用。为了从形态学上研究核内体肿胀，我们引入了一种涉及HRP催化的生物素化的核内体荧光标记新技术。在0.2 mM伯氨喹存在下，观察到直径达2 μ m的内体空泡。当除了伯氨喹之外还存在巴弗洛霉素Al时，未观察到内体肿胀，这支持了空泡质子泵活性降低伯氨喹的剂量反应的观点。讨论了对膜再循环至关重要且可能受伯氨喹影响的因素。
The anti-malaria drug primaquine is a weak base which accumulates in endosomes in a protonated form and consequently neutralises the endosomal pH, Bafilomycin Al prevents endosome acidification by inhibiting the vacuolar proton pump. Although both agents neutralise the endosomal pH, only primaquine has a strong inhibitory effect on recycling of endocytosed proteins to the plasma membrane (Van Weert et al, (1995), J, Cell Biol, 130, 821-834), This suggests that primaquine interferes with a parameter, other than endosomal pH, that is essential for membrane recycling, In the presence of 0.3 mM primaquine, endocytosed transferrin-receptors accumulated intracellularly, but not in the additional presence of bafilomycin Al. Thus, at relative low concentrations proton pump-driven accumulation of primaquine in endosomes was required to inhibit membrane recycling, suggesting that the target of primaquine is associated with endosomes, The inhibitory effect of 1 mM primaquine on transferrin receptor recycling was not reversed by the additional presence of bafilomycin Al, indicating that osmotic swelling of endosomes due to accumulation of protonated primaquine could also not explain its effect. To study endosome swelling morphologically, we introduce a novel technique for fluorescent labelling of endosomes involving HRP-catalysed biotinylation. In the presence of 0.2 mM primaquine endosomal vacuoles with diameters up to 2 mu m were observed. Endosome swelling was not observed when in addition to primaquine also bafilomycin Al was present, supporting the notion that vacuolar proton pump activity lowers the dose response for primaquine, Factors that are crucial for membrane recycling and may be affected by primaquine are discussed.