通过输血性大肠杆菌效应体EspF的WASP激活的结构机制 (U)
Hui-Chun Cheng1, Brian M Skehan, Kenneth G Campellone
1Department of Biochemistry and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
Nature
|July 25, 2008
概括
肠出血性大肠杆菌 (EHEC) 通过注射 EspF (U) 蛋白质来劫持宿主细胞的活性. 这种蛋白质结合并激活威斯科特-阿尔德里希综合征蛋白 (WASP) 家族成员,控制感染期间的活性蛋白组合.
科学领域:
- 微生物学 微生物学
- 细胞生物学 细胞生物学
- 结构生物学 结构生物学
背景情况:
- 肠道出血性大肠杆菌 (EHEC) 在感染期间操纵宿主细胞的活性细胞骨架.
- 细菌效应蛋白 EspF ((U) 被注射到宿主细胞中以控制行为动力学.
- 威斯科特-阿尔德里奇综合征蛋白 (WASP) 家族成员是活性蛋白组合的关键调节者.
研究的目的:
- 阐明EHEC的EspF(U) 蛋白激活WASP家族蛋白质的机制.
- 确定ESPF和WASP之间的相互作用的结构基础.
- 了解EHEC如何有效地劫持真核细胞骨机械.
主要方法:
- 解决方案结构的确定GTPase结合域 (GBD) -EspF(U) 复合体.
- 在体外激活WASP和神经 (N) -WASP的测试.
- 以细胞为基础的测试,观察局部化的动因组合.
主要成果:
- EspF(U) 与WASP蛋白的自身抑制性GBD结合,将其从VCA域中取代.
- 这种相互作用强烈地激活WASP和N-WASP,诱导细胞中局部化的活性蛋白组合.
- 结构显示 EspF(U) 模仿 VCA 域相互作用,竞争 GBD 结合位.
结论:
- EspF(U) 通过直接竞争 GBD 结合部位来激活 WASP,这是与真核生物激活剂不同的机制.
- 结构不相容性和高亲和度结合使EHEC能够有效地劫持宿主actin机器.
- 在WASP激活中的机制多样性可能源于其域的内在非结构性.
相关概念视频
Formation of Lipopolysaccharides
1.1K
Lipopolysaccharides (LPS) are crucial components of the outer membrane of Gram-negative bacteria, serving both structural and functional roles. It contributes to membrane stability and protects bacteria from host immune responses. LPS is composed of three major regions—lipid A, a core oligosaccharide, and an O antigen. The biosynthesis and assembly of LPS involve a highly coordinated set of enzymatic reactions and transport mechanisms. Additionally, LPS is recognized as an endotoxin,...
1.1K
Gram-negative Bacterial Protein Secretion Systems
1.7K
Gram-negative bacteria utilize sophisticated protein secretion systems to transport proteins across their double-membrane envelope into the extracellular environment or host cells. Based on their mechanism of action, these systems are classified into one-step and two-step pathways.One-Step Secretion Systems (Types I, III, IV, and VI)One-step secretion systems bypass the periplasm entirely, forming a continuous channel that spans both the inner and outer membranes:Type I Secretion System (T1SS):...
1.7K
Chemotaxis in E. coli
1.4K
Chemotaxis in Escherichia coli is a sensory-driven motility mechanism that enables bacteria to navigate chemical gradients, moving toward beneficial environments while avoiding harmful conditions. This process relies on a signal transduction system integrating external chemical cues with flagellar motor control.Chemoreceptors and Signal DetectionE. coli detects chemical gradients through methyl-accepting chemotaxis proteins (MCPs), which are membrane-bound chemoreceptors that sense attractants...
1.4K
Stringent Response in E. coli
528
Bacterial growth is closely tied to nutrient availability, with cells proliferating exponentially under favorable conditions and entering a stationary phase when resources become scarce. This transition is mediated by a regulatory mechanism known as the stringent response, which allows bacteria to adapt to nutrient deprivation by modulating gene expression and metabolic activity.During nutrient scarcity, intracellular amino acid levels decline. It results in the accumulation of uncharged tRNAs...
528
Regulation of Bacterial Virulence
76
Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...
76
Bacterial Gastroenteritis
88
Bacterial gastroenteritis, characterized by diarrhea, abdominal cramps, and vomiting, is often caused by ingestion of contaminated food or water and is frequently associated with pathogenic Escherichia coli strains. These microbes exploit two principal mechanisms to inflict disease.Shiga toxin–producing E. coli, also referred to as STEC—notably O157:H7—release Shiga toxins that target ribosomes, blocking protein synthesis. The B subunit of the toxin binds the host glycolipid...
88


