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Updated: Jun 16, 2026

13:21
In Vivo Biosensor Tracks Non-apoptotic Caspase Activity in Drosophila
Published on: November 27, 2016
Smac/DIABLOによるアポプトシス活性化の構造と生化学的基礎
Nature
|September 6, 2000
まとめ
Smac/DIABLOタンパク質は,阻害タンパク質 (IAP) に結合し,カスペスを放出することによってアポトーシスを活性化します. その構造は,機能に不可欠なホモディメア界面を明らかにし,種を超えて保存されています.
科学分野:
- 細胞生物学 細胞生物学
- バイオケミストリー バイオケミストリー
- 構造生物学 構造生物学とは
背景:
- アポトーシス,またはプログラム細胞死は,メタゾアンの発達とホメオスタシスのために不可欠であり,カスパスによって調節されます.
- アポトーシスタンパク質の阻害剤 (IAP) はカスパスを抑制し,細胞死を制御します.
- ミトコンドリアのタンパク質であるSmac/DIABLOは,IAPを抑制してアポトーシスを促進します.
研究 の 目的:
- Smac/DIABLOがアポトーシスを活性化するメカニズムを解明する.
- Smac/DIABLOの機能の構造的基盤を決定するために.
- Smac/DIABLOのホモディメリゼーションとN末端の活性における役割を調査する.
主な方法:
- 2.2A解像度でSmac/DIABLO構造を決定するためのX線結晶学.
- サイト・ディレクテッド・ミュータジェネシス (SITE-DIRECTED MUTAGENESIS) は,二次元インターフェースの機能を評価するためのものです.
- Smac/DIABLOのN端から派生したペプチドを使用して,プロカスペーゼ-3の活性化を研究するインビトロアッセイ.
主要な成果:
- Smac/DIABLOは,その機能に不可欠な,広範囲にわたる水性インターフェイスを通じてホモディメリゼーションします.
- 二次界面を破壊する突然変異は,Smac/DIABLOのプロアポプトティック活動を著しく損なう.
- Smac/DIABLOのN端からのペプチドは,ドロソフィラ菌のタンパク質に類似した,プロカスペーゼ-3をインビトロで効果的に活性化します.
結論:
- IAPとSmac/DIABLOの物理的相互作用は,プロカスペーゼ3と成熟したカスペーゼ3の両方を活性化するのに鍵となる.
- Smac/DIABLOの機能には,特定の排水性インターフェイスを通じたホモディメリゼーションが不可欠です.
- Smac/DIABLOのN端は,アポトーシスの活性化において重要な役割を果たし,進化的保存を示しています.
関連する概念動画
Apoptosis
Apoptosis is a combination of two Greek words, 'apo' and 'ptosis,' meaning separation and falling off, respectively. Hippocrates used this word to describe gangrene, which was caused due to bandaging of fractured bones. Apoptosis was distinguished from necrosis in 1970 when John Kerr reported observations of morphological changes occurring during apoptosis. During one experiment, he observed that the disruption of blood supply to the liver tissue resulted in a size reduction of the tissue.
Caspases
Caspase, a family of cysteine proteases, serve as effectors in apoptosis. The ced3 gene in C.elegans was first identified to be involved in apoptosis. This gene encodes the ced-3 caspase that is similar to the interleukin-1-beta converting enzyme or ICE in mammals. In addition to apoptosis, caspases also function in the inflammatory response. Inflammatory caspases are essential in activating pro-inflammatory cytokines that recruit immune cells and block the replication of pathogens inside cells.
The Extrinsic Apoptotic Pathway
The extrinsic apoptotic pathway is initiated when extracellular death-inducing signals, such as specific cytokines, activate the death receptors expressed on the cell surface. The immune cells involved in this pathway are natural killer cells (NK cells) and cytotoxic T-lymphocytes. NK cells are critical in innate immune response, while cytotoxic T-lymphocytes are associated with adaptive immune response. These cells recognize specific receptors expressed on the altered cells and activate...
The Intrinsic Apoptotic Pathway
Internal cellular stress, such as cellular injury or hypoxia, triggers intrinsic apoptosis. The B-cell lymphoma 2 (Bcl-2) family of proteins are the primary regulators of the intrinsic apoptotic pathway. For example, during DNA damage, checkpoint proteins, such as Ataxia Telangiectasia Mutated (ATM protein) and Checkpoints Factor-2 (Chk2) proteins, are activated. These proteins phosphorylate p53 which further activates pro-apoptotic proteins, such as Bax, Bak, PUMA, and Noxa, and inhibits...
Phagocytosis of Apoptotic Cells
Cells undergoing apoptosis form apoptotic bodies that must be removed immediately to prevent inflammation, autoimmune diseases, and necrosis. Phagocytosis is carried out by professional phagocytes such as macrophages or immature dendritic cells. Non-professional phagocytes such as epithelial cells and fibroblasts also take part in this process; however, they are not as effective as professional phagocytes.
Normal cells contain receptors that prevent them from being recognized by phagocytes.
Normal cells contain receptors that prevent them from being recognized by phagocytes.
Cellular Injury V: Apoptosis and Autophagy
Cells respond to damage and stress through highly coordinated processes that decide whether they survive or undergo controlled self-destruction. Two major pathways involved in this regulation are apoptosis, a type of programmed cell death, and autophagy, a survival mechanism that helps cells adapt to adverse conditions.ApoptosisApoptosis removes aged or injured cells to maintain tissue balance. During this process, the cell shrinks, chromatin condenses and fragments, and membrane-bound...

