内棒の組み立ては,III型分泌の注射体における針の長さを決定する
Thomas C Marlovits1, Tomoko Kubori, María Lara-Tejero
1Section of Microbial Pathogenesis, Yale University School of Medicine, Boyer Center for Molecular Medicine, New Haven, Connecticut 06536, USA.
Nature
|June 2, 2006
まとめ
バクテリアの注射体群の集合体である.
科学分野:
- 微生物学と分子生物学について
- バクテリア病原菌の発生
- 超分子組立機構 (Supramolecular Assembly) とは,超分子組立機構 (Supramolecular Assembly) と呼ばれるものです.
背景:
- 型III分泌システム (TIII SS) は,細菌の毒性にとって極めて重要であり,病原体が宿主細胞に侵入することを可能にします.
- TIII SSの重要な構成要素であるインジェキシゾームは,タンパク質の転位を担当する複雑なナノマシンです.
- インジェチゾームの正確な組み立てメカニズムを理解することは,細菌の感染戦略を解読するために不可欠です.
研究 の 目的:
- サルモネラ・タイフィミュリウムにおけるインジェクティゾームの組み立てを規制する規制メカニズムを明らかにする.
- 特定のサブストラクチャの完成が,インジェクティゾームの全体的な組み立てプロセスと機能にどのように影響するか判断する.
- InvJタンパク質が,インジェクトイソームの組み立て動態を制御する役割を調査する.
主な方法:
- サルモネラ・タイフィムリウムにおける遺伝子操作とタンパク質相互作用の研究を用いて.
- 顕微鏡と生化学分析を用いて,注射体構造と組み立て中間物質を分析する.
- 組み立て中の重要な調節タンパク質に関連した構造変化を調査する.
主要な成果:
- 内部棒の組み立ての完了が,注射器の針の構成要素の最終的なサイズを決定することを実証しました.
- InvJタンパク質が内部棒の組立を調節し,重要な制御点として作用することを示した.
- 内棒の完成時に注射体内の細胞質側における構造変化を特定し,針のタンパク質分泌を停止した.
結論:
- サルモネラ注射群の組み立ては,厳格に規制された段階的なプロセスです.
- InvJによって制御される内部棒の完成は,針の過剰延伸を防ぐ重要なチェックポイントとして機能します.
- この規制メカニズムは,有効な毒性タンパク質の供給のために,タイプIII分泌装置の適切な形成と機能を保証します.
関連する概念動画
Assembly of Cytoskeletal Filaments
18.1K
Cytoskeletal filaments are polymeric forms of smaller protein subunits. However, individual cytoskeletal filaments may easily disassemble or associate with other similar filaments to form rigid structures. Microfilaments, made of actin monomers, rely on actin-binding proteins to form bundles and create networks of individual actin filaments. Microtubules rely on microtubule-associated proteins (MAPs) to form sturdy cylindrical structures. However, the proteins involved in forming complex...
18.1K
Cytoskeletal Proteins in Bacteria
3.5K
Bacterial cells were initially considered simple, randomly organized structures lacking a cytoskeleton. However, the discovery of cytoskeleton homologs in bacteria led to the change of this opinion. Bacterial cytoskeletal filaments regulate the cell shape, cell polarity, cell division, and partitioning of plasmids during cell division. It was later discovered that bacterial cytoskeletal proteins, mainly actin and tubulin homologs, are diverse compared to their eukaryotic counterparts. On the...
3.5K
The Structure of Intermediate Filaments
4.5K
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...
4.5K
Types of Intermediate Filaments
3.7K
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...
3.7K
Formation of Intermediate Filaments
3.1K
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...
3.1K
Disassembly of Intermediate Filaments
2.0K
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...
2.0K


