Aquaporin-0 膜接口揭示了一个封闭的水孔结构
Tamir Gonen1, Piotr Sliz, Joerg Kistler
1Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, Massachusetts 02115, USA.
Nature
|May 14, 2004
概括
水素-0 (AQP0) 通过特定的蛋白质相互作用形成透镜膜结点. 确定的AQP0结结构揭示了一个封闭的水孔,与其他水不同,表明了一个新的封闭机制.
科学领域:
- 结构生物学是结构生物学.
- 膜生物物理学 膜生物物理学
- 眼睛生理学 眼睛生理学
背景情况:
- 水素-0 (AQP0) 是唯一一种水素,它在眼镜内形成体内膜结.
- 了解AQP0的结构对于透镜透明度和水分化至关重要.
研究的目的:
- 为了确定AQP0膜结的高分辨率结构.
- 为了阐明调解AQP0结形成的分子相互作用.
- 为了研究交叉点内的AQP0水孔的功能状态.
主要方法:
- 电子晶体学被用来确定AQP0膜结结构.
- 从透镜芯,包括裂开的形式,分析AQP0,以回顾体内连接.
主要成果:
- AQP0连接由三种局部的分子间相互作用形成的双层晶体组成.
- 保存的プロ林残留物是这些相互作用的关键媒介,在水族中是独一无二的.
- 接口中的AQP0水孔处于封闭的构造,具有额外的收缩.
- 这与以前在所有研究的水族中观察到的开放孔状结构不同.
结论:
- AQP0结结构揭示了透镜细胞-细胞粘附的新机制.
- 封闭的水孔和独特的收缩表明AQP0.0具有特定的封闭功能.
- 这些发现提供了对透镜发育,功能和潜在病理学的见解.
相关概念视频
00:43Pinocytosis
Cells use energy-requiring bulk transport mechanisms to transfer large particles, or large amounts of small particles, into or out of the cell. The cells envelop the particles in spherical membranes called vesicles or vacuoles. Vesicles that transport material into the cell are built from the cell membrane. These vesicles encapsulate external molecules and transport them into the cell in a process called endocytosis.
00:38Pinocytosis
Cells use energy-requiring bulk transport mechanisms to transfer large particles or large numbers of small particles into or out of the cell. The cells envelop the particles in spherical membranes called vesicles or vacuoles. Vesicles that transport material into the cell are built from the cell membrane. These vesicles encapsulate external molecules and transport them into the cell in a process called endocytosis.
Pinocytosis ("cellular drinking") is one of three main types of endocytosis. In...
Pinocytosis ("cellular drinking") is one of three main types of endocytosis. In...
01:25Aquaporins
Aquaporins or AQPs are a family of integral membrane proteins whose primary function is to transport water, while some called aquaglyceroporins also transport glycerol. In addition, aquaporins have also been suspected to be involved in transporting volatile substances, such as carbon dioxide and ammonia, across membranes. Such AQPs that act as gas channels are often highly expressed in cells involved in the gaseous exchange, such as red blood cells, epithelial cells, and pulmonary capillaries.
01:09Multi-pass Transmembrane Proteins and β-barrels
In multi-pass transmembrane proteins, the polypeptide chain crosses the membrane more than once. The transmembrane polypeptide chain either forms an α-helix or β-strand structure. α-Helix containing multi-pass transmembrane proteins are ubiquitous, whereas β-strand containing ones are mainly found in gram-negative bacteria, mitochondria, and chloroplasts.
α-Helix containing multi-pass transmembrane proteins
Multi-pass transmembrane proteins such as G-protein-linked receptors (GPCRs) and...
α-Helix containing multi-pass transmembrane proteins
Multi-pass transmembrane proteins such as G-protein-linked receptors (GPCRs) and...
01:21Structure of Porins
Mitochondria, chloroplasts, and gram-negative bacteria have transmembrane, beta-barrel proteins called porins to mediate the free diffusion of ions and metabolites across the membrane. Mitochondrial porin precursors contain conserved amino acid sequences called beta signals at their C-terminal. Beta signals have a motif of PoXGXXHyXHy (Po-Polar, X-Any amino acid, G-Glycine, Hy-LargeHydrophobic), which are crucial for precursor recognition to initiate precursor assembly. Beta-barrel precursors...
01:29Tight Junctions
Tight junctions are molecular seals between cells that prevent the leaking of fluids, ions, and other small solutes across cavities and compartments in multicellular organisms. They are mainly composed of claudin and occludin transmembrane proteins, and other proteins such as tricellulin and JAM (junctional adhesion molecule). All these proteins are 4-pass transmembrane proteins, except JAM, which is a single-pass transmembrane protein belonging to the immunoglobulin superfamily. The...