単分子移動マッピングは,小 (1 kDa) 溶液の阻害のない細胞内拡散を示しています
Alexander A Choi1, Limin Xiang1, Wan Li1
1Department of Chemistry, University of California, Berkeley, California 94720, United States.
Journal of the American Chemical Society
|April 7, 2023
まとめ
小さな分子の細胞内拡散は以前考えられていたより速く,ほとんどの細胞空間は水のような動きを可能にします. マクロ分子混雑は,この拡散速度に最小限の影響を及ぼします.
科学分野:
- 細胞生物学
- バイオ物理学
- 分子力学
背景:
- 小さな溶液 (1 kDa) の細胞内拡散は重要ですが,研究することは困難です.
- 以前の方法では,迅速な拡散係数 (> 300 μm2/s) を標識し測定することが困難でした.
研究 の 目的:
- 哺乳類の細胞内の小さな溶液の変換的拡散を定量化し,空間的にマッピングする.
- 高い拡散係数を測定する際の限界を克服し,局所的な拡散変動を解決する.
主な方法:
- 超解像度技術である単分子移動/拡散マッピング (SMdM) を利用した.
- タンデムストロボスコープ照明パルスを使用し,距離は400μsである.
- 水溶性染料と染料でタグ付けされた核酸にこの方法を適用した.
主要な成果:
- 細胞内拡散はほとんど阻害されず,in vitroの60~70% (~250μm2/sまで) に達することが示された.
- 空間的な解像度の必要性を強調する,非常に遅い拡散のサブマイクロメートル領域を特定しました.
- サイトゾールの粘度が控えめで,マクロ分子混雑が大きな障害ではないことが示された.
結論:
- 小さな溶液の細胞内拡散は,マクロ分子混雑ではなく,主に細胞溶液の粘度によって制限されます.
- この研究は,細胞内拡散速度制限が低いという以前の仮定に異議を唱える.
- 細胞内の分子輸送を理解するために,空間的に解明された拡散マッピングは不可欠です.
関連する概念動画
01:24Protein Diffusion in the Membrane
4.4K
Proteins show rotational as well as lateral diffusion across the membrane. The lateral diffusion of proteins was confirmed through the cell fusion experiment where mouse and human cells were fused, resulting in hybrid cells. When the human and mouse cells fused, the specific membrane proteins on human and mouse cells were marked with the red and green-fluorescent markers, respectively. Initially, the red and green fluorescence was located on the respective hemisphere of the cell. As time...
4.4K
01:19Protein Dynamics in Living Cells
2.2K
Different fluorescence-based techniques are used to study the protein dynamics in living cells. These techniques include FRAP, FRET, and PET.
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
2.2K
01:16Facilitated Diffusion
527
The plasma membrane, a critical structure in cellular biology, houses an array of transporters, or carrier proteins, interspersed within its lipid bilayer. These proteins play a crucial role in solute transport through facilitated diffusion, a form of passive diffusion that uses transporters to move the molecules across the membrane.
In this process, substrates such as organic compounds and ions interact with a transporter on one side, triggering conformational changes in proteins that enable...
In this process, substrates such as organic compounds and ions interact with a transporter on one side, triggering conformational changes in proteins that enable...
527