まとめ
研究者らは,マウスの表皮ケラチン中間線維子ユニットの主要な構造を決定した. これは,ケラチンフィラメント組織にとって極めて重要な,グリシンに富んだ端末ドメインを持つコイルコイルコア構造を明らかにします.
科学分野:
- バイオケミストリー バイオケミストリー
- 分子生物学は分子生物学である.
- 構造生物学 構造生物学とは
背景:
- 中間繊維は細胞骨格の重要な構成要素である.
- ケラチンは,上皮細胞の中間フィラメントの主要なクラスを形成します.
- ケラチンの構造を理解することは,細胞のメカニズムと発達の鍵です.
研究 の 目的:
- ネズミの表皮ケラチン中間線維子ユニットの完全な一次構造を決定する.
- ケラチン繊維の構造的組織を解明する.
主な方法:
- cDNAクローンのヌクレオチド配列決定.
- 構造的モチーフのためのタンパク質配列の分析.
- ケラチン繊維の限られたキモトリプティックな消化.
主要な成果:
- 59 kDaのマウス表皮ケラチンサブユニットの完全なプライマリ構造が決定されました.
- このタンパク質は,中心部にアルファヘリカルドメインを備えている.
- タンデムペプチドの繰り返しを持つ非アルファヘリカル,グリシンに富んだ末端ドメインが特定されました.
結論:
- ケラチン繊維は,保存されたコアと突起の端末領域を持つ構造的組織を有しています.
- グリシンに富んだ端末は,おそらく,光線の組み立てと相互作用に役割を果たしている.
- 決定された構造は,中間のフィラメントタンパク質アーキテクチャの洞察を提供します.
関連する概念動画
Structural Protein Function
Structural proteins are a category of proteins responsible for functions ranging from cell shape and movement to providing support to major structures such as bones, cartilage, hair, and muscles. This group includes proteins such as collagen, actin, myosin, and keratin.
Collagen, the most abundant protein in mammals, is found throughout the body. In connective tissue, such as skin, ligaments, and tendons, it provides tensile strength and elasticity. In bones and teeth, it mineralizes to form...
Collagen, the most abundant protein in mammals, is found throughout the body. In connective tissue, such as skin, ligaments, and tendons, it provides tensile strength and elasticity. In bones and teeth, it mineralizes to form...
Introduction to Actin
Actin is a highly conserved cytoskeletal protein found abundantly in eukaryotic cells. It constitutes 10% weight of the total cellular protein in muscle cells, while in non-muscle cells, it is lower and makes up around 1–5 percent of the total cell protein. Actin found in the unicellular amoebae and complex multicellular animals is around 80% similar, demonstrating their conservation over a billion years of evolution. Actin coding genes are conserved within species and across different species.
The Structure of Intermediate Filaments
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 filaments...
Intermediate filaments...
Types of Intermediate Filaments
The intermediate filaments are an essential component of the cytoskeleton. Presently six types of intermediate filament have been identified. Type I and II are acidic and basic keratin proteins. Type III is of mesodermal origin and comprises four proteins: vimentin, desmin, glial fibrillary acidic protein (GFAP), and peripherin. Vimentin is commonly found in mesenchymal cells, desmin in muscle cells, GFAP in astrocytes, while peripherin is found in peripheral nervous system neurons (PNS). Type...
Formation of Intermediate Filaments
Intermediate filaments are cytoskeletal proteins with higher tensile strength and flexibility than microfilaments and microtubules. Unlike the other two cytoskeletal proteins, intermediate filament formation lacks the enzymatic activity to hydrolyze nucleotides like ATP and GTP to generate energy for polymerization. Therefore, the formation of intermediate filaments is multistep self-assembly. The involvement of any accessory proteins in intermediate filament formation has not yet been reported.
Disassembly of Intermediate Filaments
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...


