人間の心臓のミオシンフィラメントの冷凍-EM構造
Debabrata Dutta1, Vu Nguyen2, Kenneth S Campbell3
1Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Chan Medical School, Worcester, MA, USA. debabrata.dutta@umassmed.edu.
Nature
|November 2, 2023
まとめ
心臓のミオシンフィラメント構造が解明され,ミオシン,cMyBP-C,およびチチンが心臓の収縮を制御するためにどのように相互作用するかが明らかになりました. この画期的な発見は 筋肉の機能と疾患のメカニズムを 説明し 新しい心不全治療法への道を開きます
科学分野:
- バイオ物理学
- 分子生物学
- 心血管科学
背景:
- 心筋の収縮は ミオシンとアクチン繊維に依存しています
- 心臓のミオシン結合タンパク質C (cMyBP-C) とチチンは,重要な構造的および調節的成分です.
- これらのタンパク質の変異は心不全につながるが,その正確な構造的な役割は不明であった.
研究 の 目的:
- 人間の心臓のミオシンフィラメントの分子構造,特にcMyBP-Cを含む領域を決定する.
- 心臓フィラメント内のミオシン,cMyBP-C,およびチチンの相互作用を解明する.
- 心筋の機能,調節,疾患を理解するための構造的基礎を提供すること.
主な方法:
- 3D構造を再現するために,冷凍電子顕微鏡 (cryo-EM) が使用されました.
- ミオシンヘッドモチーフ,テールパッキング,cMyBP-Cとチチンの相互作用を含む,フィラメントの構造の分析.
主要な成果:
- この研究は,フィラメント内のチチンとcMyBP-Cの詳細な構造を明らかにする.
- ミオシンの運動領域は3つの異なるモチーフを形成し,機能的な柔軟性と他の構成要素との相互作用を可能にします.
- 線維の脊髄におけるミオシン尾の詰め込みと,制御タンパク質の正確な配置が解明された.
結論:
- 解明された構造は,心臓筋の構造と機能を解釈するための新しいパラダイムを提供します.
- 超リラックス状態におけるcMyBP-Cと長さ依存活性化におけるチチン/cMyBP-Cの役割を説明する.
- これらの相互作用を理解することで,突然変異によって引き起こされる病気のメカニズムを洞察し,心不全の治療法の開発を導くことができます.
関連する概念動画
Overview of Myosin Structure and Function
4.4K
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...
4.4K
Cryo-electron Microscopy
3.3K
Conventional electron microscopy (EM) involves dehydration, fixation, and staining of biological samples, which distorts the native state of biological molecules and results in several artifacts. Also, the high-energy electron beam damages the sample and makes it difficult to obtain high-resolution images. These issues can be addressed using cryo-EM, which uses frozen samples and gentler electron beams. The technique was developed by Jacques Dubochet, Joachim Frank, and Richard Henderson, for...
3.3K
Structure of Cardiac Muscles
11.9K
Cardiac muscle, or myocardium, is a specialized type of muscle found exclusively in the heart. Its unique structural and functional characteristics enable the heart to perform its vital role of pumping blood throughout the body continuously and rhythmically. The cardiac muscle cells, or cardiomyocytes, possess an endomysium and perimysium but do not have an epimysium.
Compared to skeletal muscles, cardiac muscle cells are small and mostly have a single nucleus. Additionally, they are usually...
Compared to skeletal muscles, cardiac muscle cells are small and mostly have a single nucleus. Additionally, they are usually...
11.9K
The Structure of Intermediate Filaments
4.0K
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...
4.0K
ATP Synthase: Structure
12.5K
ATP synthase or ATPase is among the most conserved proteins found in bacteria, mammals, and plants. This enzyme can catalyze a forward reaction in response to the electrochemical gradient, producing ATP from ADP and inorganic phosphate. ATP synthase can also work in a reverse direction by hydrolyzing ATP and generating an electrochemical gradient. Different forms of ATP synthases have evolved special features to meet the specific demands of the cell. Based on their specific feature, ATP...
12.5K
The Sarcomere
8.2K
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...
Each...
8.2K


