人体IAPP纤维的结构反映了膜和pH条件
Venus Singh Mithu1, Karin Giller1, Evgeny Nimerovsky1
1Department of NMR-based Structural Biology, Max Planck Institute of Multidisciplinary Sciences, Göttingen 37077, Germany.
Journal of the American Chemical Society
|August 1, 2025
概括
在2型糖尿病中,生理学相关的模型揭示了人类小岛氨基聚 (hIAPP) 纤维的结构. 膜相互作用和细胞外pH对于理解hIAPP聚合和β细胞功能障碍至关重要.
科学领域:
- 生物物理
- 结构生物学
- 生物化学
背景情况:
- 人类小岛粉样蛋白聚合 (hIAPP) 与2型糖尿病和β细胞功能障碍有关.
- 现有的体外模型往往缺乏生理相关性,无法考虑膜相互作用和原生pH值.
- 关于hIAPP外体纤维的结构数据很少,这阻碍了对疾病机制的全面了解.
研究的目的:
- 确定在生理相关条件下形成的hIAPP纤维的高分辨率结构,特别是涉及脂膜和细胞外pH值.
- 在膜环境中研究hIAPP的结构可塑性.
- 了解2型糖尿病中hIAPP介导的β细胞功能障碍的结构基础.
主要方法:
- 使用固态NMR光谱分析hIAPP纤维.
- 在细胞外pH (7.4) 和细胞内pH (5.3) 的情况下,形成了纤维.
- 结构特征侧重于原纤维结构,N端和C端区域以及整体折叠.
主要成果:
- 在pH 7.4形成的膜介导的hIAPP纤维是均的,采用具有明显N端β链的L形原纤维结构.
- 纤维细胞核 (N14-L27) 呈现着保存的CF1折叠,一种非脂质纤维细胞中也存在的β弧结构.
- 在细胞内pH (5.3) 形成的纤维在结构上异质,在C端有差异,表明hIAPP在膜环境中的结构性可塑性.
结论:
- 这项研究提供了第一个在生理上相关的细胞外条件下的膜介导hIAPP纤维的高分辨率结构.
- hIAPP表现出显著的结构可塑性,从螺旋性单体过渡到β-毛寡合体和β-弧度丰富的纤维.
- 准确的粉样蛋白聚合模型需要考虑膜相互作用和本地pH,以了解疾病病理.
更多相关视频
10:49Method to Visualize and Analyze Membrane Interacting Proteins by Transmission Electron Microscopy
Published on: March 5, 2017
13.4K
07:26Single-molecule Super-resolution Imaging of Phosphatidylinositol 4,5-bisphosphate in the Plasma Membrane with Novel Fluorescent Probes
Published on: October 15, 2016
9.6K
相关概念视频
Amyloid Fibrils
9.9K
Amyloid fibrils are aggregates of misfolded proteins. Under most circumstances, misfolded proteins are either refolded by chaperone proteins or degraded by the proteasome. However, in the case of a mutation or a disease, these proteins can accumulate to form large clusters and often further assemble to form elongated fibers, called fibrils.
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining,...
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining,...
9.9K
Formation of Higher-order Actin Filaments
3.1K
The polymerization of G-actin monomers into filamentous F-actin is a multi-step process. Once the F-actins are formed, they can bundle together in different arrangements to form higher-order networks and regulate cellular functions. Common examples include the formation of lamellipodia and filopodia at the cell's leading edge by actin reorganization in a migrating cell. The microvilli on the brush border epithelial cells are also formed through the F-actin network.
The high-order actin...
The high-order actin...
3.1K
The Structure of Intermediate Filaments
4.2K
The intermediate filaments are one of three widely studied cytoskeletal filaments. They are so named as their diameter (10 nm) is in between that of microfilaments (7 nm) and the microtubules (25 nm). These filaments are highly stable and can remain intact when exposed to high salt concentrations and detergents. These filaments are responsible for providing stability and mechanical support to the cells. They also help in cell adhesion and maintaining tissue integrity.
Intermediate...
Intermediate...
4.2K
Asymmetric Lipid Bilayer
7.7K
Biological membranes show uneven distribution of different types of lipids in the inner and outer layers, resulting in transverse asymmetric membranes. The treatment of the erythrocyte membrane with the enzyme phospholipase confirmed the asymmetric nature of the lipid bilayer. The enzyme hydrolyzes lipids into fatty acids and hydrophilic groups. The phospholipase acts only on the outer layer of the membrane, while the inner layer remains intact. The phospholipase treatment resulted in 80%...
7.7K
Disassembly of Intermediate Filaments
2.1K
Intermediate filaments (IFs) do not undergo spontaneous disassembly. Enzymes, kinases, and phosphatases add and remove phosphates from specific sites to regulate their disassembly. The IF concentration in the cytoplasm also regulates the disassembly. If the concentration crosses a threshold, it activates the protein kinases in the vicinity, allowing the phosphorylation of IFs.
Keratin proteins, found at the cell periphery near cell junctions, undergo a cycle of assembly and disassembly. In Type...
Keratin proteins, found at the cell periphery near cell junctions, undergo a cycle of assembly and disassembly. In Type...
2.1K
Membrane Domains
5.8K
The membrane domains concentrate specific lipids and proteins at one place within the membrane, which helps in cell signaling, adhesion, and other critical cellular processes. These domains can differ in size, composition, function, and lifespan.
Protein Domains
The membrane comprises a group of distinct proteins responsible for carrying out a cell's specific function. For example, the plasma membrane of the human sperm, or a single germ cell, contains a unique set of proteins in the...
Protein Domains
The membrane comprises a group of distinct proteins responsible for carrying out a cell's specific function. For example, the plasma membrane of the human sperm, or a single germ cell, contains a unique set of proteins in the...
5.8K
