Islet amyloid polypeptide forms rigid lipid-protein amyloid fibrils on supported phospholipid bilayers
Islet amyloid polypeptide forms rigid lipid-protein amyloid fibrils on supported phospholipid bilayers
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DOI：
10.1016/j.jmb.2007.11.077
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发表时间：
2008-02-08
影响因子：
5.6
通讯作者：
Kinnunen, Paavo K. J.
中科院分区：
文献类型：
--
作者：
Domanov, Yegor A.;Kinnunen, Paavo K. J.
胰岛淀粉样蛋白多肽（IAPP）在2型糖尿病患者的胰岛形成纤维状淀粉样蛋白沉积，其错误折叠和聚集被认为是导致β细胞死亡的原因。越来越多的证据表明，IAPP的成纤维化受到脂质膜的强烈影响，反之亦然，淀粉样蛋白的生长严重影响了膜的结构和完整性。在这里，我们报告了在支持的脂质膜表面伴随IAPP成纤维的形态变化的直接荧光显微镜观察。在亚微摩尔浓度的应用几分钟内，IAPP引起了广泛的膜重塑，包括形成缺陷、囊泡和小管。考察了IAPP浓度、离子强度和淀粉样蛋白种子的存在对双分子层扰动和肽聚集的影响。用荧光标记IAPP或硫黄酮T染色观察淀粉样蛋白原纤维的生长。肽和膜的双色成像显示原纤维最初仅由肽组成，并且在生长的纤维接触脂质膜的点上发生囊泡。有趣的是，培养2-5小时后，IAPP纤维被支撑膜衍生的脂质膜“包裹”。福斯特共振能量转移光谱证实了成熟纤维中淀粉样蛋白和膜之间的分子水平关联的逐渐增加。(C) 2007 Elsevier Ltd.版权所有。
Islet amyloid polypeptide (IAPP) forms fibrillar amyloid deposits in the pancreatic islets of Langerhans of patients with type 2 diabetes mellitus, and its misfolding and aggregation are thought to contribute to beta-cell death. Increasing evidence suggests that IAPP fibrillization is strongly influenced by lipid membranes and, vice versa, that the membrane architecture and integrity are severely affected by amyloid growth. Here, we report direct fluorescence microscopic observations of the morphological transformations accompanying IAPP fibrillization on the surface of supported lipid membranes. Within minutes of application in submicromolar concentrations, IAPP caused extensive remodeling of the membrane including formation of defects, vesiculation, and tubulation. The effects of IAPP concentration, ionic strength, and the presence of amyloid seeds on the bilayer perturbation and peptide aggregation were examined. Growth of amyloid fibrils was visualized using fluorescently labeled IAPP or thioflavin T staining. Two-color imaging of the peptide and membranes revealed that the fibrils were initially composed of the peptide only, and vesiculation occurred in the points where growing fibers touched the lipid membrane. Interestingly, after 2-5 h of incubation, IAPP fibers became "wrapped" by lipid membranes derived from the supported membrane. Progressive increase in molecular-level association between amyloid and membranes in the maturing fibers was confirmed by Forster resonance energy transfer spectroscopy. (C) 2007 Elsevier Ltd. All rights reserved.