通过caspase-1适配器ASC和Ipaf的炎症酶的差异激活
Sanjeev Mariathasan1, Kim Newton, Denise M Monack
1Molecular Oncology Department, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, USA.
Nature
|June 11, 2004
概括
适配器ASC对于炎症酶激活和随后的IL-1β/IL-18成熟至关重要. Ipaf 特别介导细胞内病原体的 caspase-1 激活,影响炎症和细胞死亡途径.
科学领域:
- 免疫学 免疫学 免疫学
- 细胞生物学 细胞生物学
- 分子生物学分子生物学
背景情况:
- 启动器卡斯帕斯由特定的适配器调节,如FADD和Apaf-1.
- 炎症组复合体含有ASC,Ipaf和RIP2等适配器,可以激活caspase-1 (中白素-1转化酶).
研究的目的:
- 调查ASC,Ipaf和RIP2适配器在炎症细胞功能中的作用.
- 阐明这些适配体对酶-1激活和下游炎症反应的具体贡献.
主要方法:
- 使用了基因缺陷巨细胞 (ASC-, Ipaf-, RIP2-null) 和小鼠.
- 刺激的巨细胞与细胞外ATP,收费类受体 (TLR) 激动剂,以及细胞内病原体 (Salmonella typhimurium).
- 评估了卡斯帕酶-1激活,IL-1β和IL-18成熟,内毒性冲击耐药性和病原体诱导的细胞死亡.
主要成果:
- 缺少ASC取消了细胞外ATP驱动的caspase-1激活,IL-1β/IL-18成熟和内毒性休克.
- 在对S. typhimurium的反应中,ASC-null巨体显示严重受损的caspase-1激活.
- 艾帕夫缺乏症会受到S. typhimurium的卡斯帕-1激活功能损害,但不是通过TLR加ATP刺激.
- RIP2的缺陷没有影响caspase-1的激活.
- 在ASC或IPAF缺乏的细胞中,由卡斯帕酶-1引发的刺激引发的巨细胞死亡被废除.
结论:
- ASC对于炎症酶介导的caspase-1激活至关重要,对于炎症性细胞因子成熟和宿主防御至关重要.
- Ipaf作为一种特定的通路,用于由细胞内病原体激活炎症酶.
- 炎酶介导炎症和细胞死亡途径之间存在显著联系,由ASC和Ipaf.介导.
相关概念视频
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...
MAPK Signaling Cascades
Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
The JAK-STAT Signaling Pathway
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...
cAMP-dependent Protein Kinase Pathways
Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...


