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Updated: Jul 3, 2026
06:53
Probing Myosin Ensemble Mechanics in Actin Filament Bundles Using Optical Tweezers
Published on: May 4, 2022
ミオシンIは,分子力センサーとして作用します.
Joseph M Laakso1, John H Lewis, Henry Shuman
1Pennsylvania Muscle Institute and Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
Science (New York, N.Y.)
|July 5, 2008
まとめ
運動タンパク質であるミオシンIは,細胞の緊張に反応して運動を劇的に変化させることで,分子力センサーの役割を果たします. この緊張感は,様々な細胞機能に不可欠である.
科学分野:
- 細胞生物学 細胞生物学
- バイオフィジックス 生物物理学
- 分子モーターは分子モーターです.
背景:
- 聴覚や膜輸送などの細胞プロセスは,分子緊張感を感知することに依存しています.
- ミオシンIは,これらの緊張に依存する細胞機能に関与する運動タンパク質です.
研究 の 目的:
- ミオシンIの運動特性が,異なる分子張力下でどのように変化するかを調査するために.
- ミオシンIが分子力センサーとして機能するかどうかを判断する.
主な方法:
- 光学トラップを使用して,単一のミオシンI分子の位移を測定しました.
- 異なる張力レベル下でミオシンIのアクチン結合運動を決定した.
主要な成果:
- ミオシンIがアクチンから離れる速度は,2ピコニュートン以下で75倍以上低下しました.
- ミオシンIは,電圧下での低デュート比 (<0.2) から高デュート比 (>0.9) に移行した.
結論:
- ミオシンIは著しい緊張感を示し,分子力センサーとして機能します.
- この特性は,力検出を必要とする細胞プロセスにおけるミオシンIの役割をサポートします.
関連する概念動画
01:15Overview of Myosin Structure and Function
Myosins are a family of molecular motor proteins, first identified in the skeletal muscles, where they are responsible for muscle contraction. Along with their role in muscle contraction, these proteins also play a role in the intracellular transport of molecules and vesicles. There are twenty-four classes of myosins based on their domain sequence and organization. Of the twenty-four, six classes (Myosin I, Myosin II, Myosin V, Myosin VI, Myosin VII, and Myosin X) have been well characterized.
01:16Actin and Myosin in Muscle Contraction
Actin and myosin are contractile proteins that form the sarcomere found in skeletal muscle tissues for regulating muscle contraction. Actin, a globular contractile protein, interacts with myosin for muscle contraction. The skeletal tissue appears striped or striated under a microscope due to the repeated arrangement of contractile proteins actin and myosin along the length of myofibrils. Dark A bands and light I bands repeat along myofibrils, and the alignment of myofibrils in the cell causes...
01:18Role of Myosin in Cell Migration
Myosins are multimeric motor proteins involved in various cellular processes such as migration, adhesion, and proliferation. Myosin II is the most common type in animal cells, which binds and cross-links actin filaments.
Myosin II is a hexamer comprising two heavy chains with globular heads and coiled-coil tails, two regulatory light chains, and two essential light chains. The ATPase sites on the myosin heads hydrolyze ATP, and the released phosphate generates the force for contraction. It is...
Myosin II is a hexamer comprising two heavy chains with globular heads and coiled-coil tails, two regulatory light chains, and two essential light chains. The ATPase sites on the myosin heads hydrolyze ATP, and the released phosphate generates the force for contraction. It is...
01:58Mechanical Protein Functions
Proteins perform many mechanical functions in a cell. These proteins can be classified into two general categories- proteins that generate mechanical forces and proteins that are subjected to mechanical forces. Proteins providing mechanical support to the structure of the cell, such as keratin, are subjected to mechanical force, whereas proteins involved in cell movement and transport of molecules across cell membranes, such as an ion pump, are examples of generating mechanical force.
01:08The Sarcomere
A sarcomere is a microscopic segment repeating in a myofibril. The sarcomere fundamentally consists of two main myofilaments: thick filaments called myosin and thin filaments called actin. These filaments interact by sliding past each other in response to stimulus. In addition to myosin and actin, several other proteins, such as tropomyosin, troponin, titin, nebulin, myomesin, α-actinin, and dystrophin, play crucial roles in regulating, structuring, and functioning of the sarcomere.
Each myosin...
Each myosin...
01:10The Role of Actin and Myosin in Non-muscle Cells
Actin and myosin or actomyosin filaments also play a significant role in cells other than those involved in muscle contraction (which occurs within the sarcomere of muscle cells). The mechanism of non-muscle cell contractile bundles was first observed in Dictyostelium and Acanthamoeba. In non-muscle cells, two bundles are commonly found: stress fibers and actomyosin adherence belts. These contractile bundles are smaller and less organized than the ones found in muscle cells. They are held...