Magainin 2 in Action: Distinct Modes of Membrane Permeabilization in Living Bacterial and Mammalian Cells
Magainin 2 in Action: Distinct Modes of Membrane Permeabilization in Living Bacterial and Mammalian Cells
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DOI：
10.1529/biophysj.108.133488
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发表时间：
2008-12-15
影响因子：
3.4
通讯作者：
Matsuzaki, Katsumi
中科院分区：
文献类型：
--
作者：
Imura, Yuichi;Choda, Naoki;Matsuzaki, Katsumi
尽管模型膜已被广泛用于阐明肽如何透化膜，但阳离子抗菌肽与活细菌和哺乳动物细胞的相互作用知之甚少。在这项研究中，使用共聚焦激光扫描显微镜研究了 F5W-magainin 2 (GIGKWLHSAKKFGKAFVGEIMNS)（从非洲爪蛙非洲爪蟾中分离出来的 magainin 2 的等效类似物）与未固定的巨大芽孢杆菌和中国仓鼠卵巢 (CHO)-K1 细胞的相互作用。将少量四甲基罗丹明标记的 F5W-magainin 2 掺入未标记的肽中以进行成像。不同大小的荧光标记物流入细胞质表明，magainin 2 以显着不同的方式透化细菌和哺乳动物细胞膜。该肽在细胞质中形成直径约2.8 nm（23 nm）的孔，并伴有膜出芽和脂质翻转，主要积聚在线粒体和细胞核中。三磷酸腺苷和带负电荷的糖胺聚糖很少参与 CHO-K1 细胞中马加宁诱导的膜透化。此外，发现CHO-K1细胞对magainin的敏感性与红细胞相似。因此，据我们所知，细菌和哺乳动物细胞中magainin 2独特的膜透化过程首次被详细地可视化和表征。
Interactions of cationic antimicrobial peptides with living bacterial and mammalian cells are little understood, although model membranes have been used extensively to elucidate how peptides permeabilize membranes. In this study, the interaction of F5W-magainin 2 (GIGKWLHSAKKFGKAFVGEIMNS), an equipotent analogue of magainin 2 isolated from the African clawed frog Xenopus laevis, with unfixed Bacillus megaterium and Chinese hamster ovary (CHO)-K1 cells was investigated, using confocal laser scanning microscopy. A small amount of tetramethylrhodamine-labeled F5W-magainin 2 was incorporated into the unlabeled peptide for imaging. The influx of fluorescent markers of various sizes into the cytosol revealed that magainin 2 permeabilized bacterial and mammalian membranes in significantly different ways. The peptide formed pores with a diameter of similar to 2.8 nm (23 nm) into the cytosol, accompanied by membrane budding and lipid flip-flop, mainly accumulating in mitochondria and nuclei. Adenosine triphosphate and negatively charged glycosaminoglycans were little involved in the magainin-induced permeabilization of membranes in CHO-K1 cells. Furthermore, the susceptibility of CHO-K1 cells to magainin was found to be similar to that of erythrocytes. Thus, the distinct membrane-permeabilizing processes of magainin 2 in bacterial and mammalian cells were, to the best of our knowledge, visualized and characterized in detail for the first time.