炎症性カスパース-4によるサイトカイン分裂に関する構造的洞察
Pascal Devant1, Ying Dong2,3, Julian Mintseris4
1Division of Gastroenterology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA.
Nature
|November 22, 2023
まとめ
人間のカスパース-4は,炎症体とカスパース-1をバイパスしてインタールイキン-18 (IL-18) を割ります. Cryo-EMは,ガスダーミンDとは異なるカスパース-4サイトカイン処理と基板捕獲の構造的メカニズムを明らかにします.これは先天的な免疫研究に影響します.
科学分野:
- 免疫学
- 構造生物学
- 生物化学
背景:
- 炎症性カスパスは先天的な免疫に不可欠で IL-1ファミリーのメンバーのような サイトカインを処理します
- カノニカル・インフラマソームとカスパース-1は,伝統的にプロ-IL-1βとプロ-IL-18を分裂することが知られている.
- 炎症性カスパース媒介のサイトカイン処理の構造的基礎は,大部分が未定義のままである.
研究 の 目的:
- プロIL-18処理におけるヒトカスパース-4の役割を調査する.
- カスパース-4が基質と相互作用する構造的メカニズムを解明する.
- カスパース-4が,正規の炎症体とは独立してIL-18の放出にどのように貢献するのかを理解する.
主な方法:
- プロ-IL-18におけるカスパース-4の分裂活性を評価する生化学的測定法
- 低温電子顕微鏡 (cryo-EM) で,カスパース-4-プロ-IL-18複合体の構造を決定する.
- ガスダーミンDによる基板結合および裂解機構の比較分析
主要な成果:
- 人間のカスパース-4は,カスパース-1と同様にプロ-IL-18を効率的に割ります.
- カスパース4がプロIL-18とガスダーミンDの両方を割る能力は, kanonical inflammasomesなしでIL-18の放出を可能にします.
- 活性サイトとエクソサイトの相互作用を含む,カスパース-4とプロIL-18の間の2つの異なる相互作用が,クリオ・エムによって明らかになった.
- サイトカイン基板の捕獲と分裂のメカニズムは,ガスダーミンDのメカニズムとは異なる.
結論:
- 人体カスパース-4は,重要なプロ-IL-18処理活性を持ち,IL-18の放出のための代替経路を提供しています.
- 構造的な洞察は,先天的免疫および炎症性疾患におけるカスパース-4の機能を理解するための枠組みを提供します.
- これらの発見は,IL-18の処理におけるカスパース-1の独占的な役割に異議を唱え,カスパース-4のより広範な基板特異性を強調しています.
関連する概念動画
Caspases
12.5K
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...
12.5K
The Extrinsic Apoptotic Pathway
6.4K
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...
6.4K
The Intrinsic Apoptotic Pathway
6.6K
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...
6.6K
Phagocytosis of Apoptotic Cells
3.9K
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...
Normal cells contain receptors that prevent them from being recognized...
3.9K
The JAK-STAT Signaling Pathway
8.9K
Several cytokine receptors have tightly bound Janus kinase or JAK proteins attached at their cytosolic tail. Small signaling molecules such as cytokines, growth hormones, or prolactins bind to the cytokine receptors and initiate their dimerization. The dimerization brings the cytosolic JAKs together that trans-phosphorylate and activates each other. The activated JAKs now phosphorylate cytosolic tails of the cytokine receptors, which serve as binding sites for adaptor proteins such as SH2...
8.9K
Apoptosis
11.5K
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...
11.5K


