外膜不稳定的机制是由于蛋白质含量总体减少而导致的
Irina V Mikheyeva1, Jiawei Sun2, Kerwyn Casey Huang3,4,5
1Department of Molecular Biology, Princeton University, Princeton, NJ, 08540, USA.
Nature communications
|September 15, 2023
概括
阴性细菌中BamD的损失会削弱外膜 (OM),导致破裂. 抑制器突变通过阻止脂去除来防止破裂,但不会恢复OM刚性或细胞形状.
科学领域:
- 微生物学 微生物学
- 细胞生物学 细胞生物学
- 生物化学 生物化学
背景情况:
- 阴性细菌具有不对称的外膜 (OM),外侧的叶片中含有脂多糖 (LPS).
- 具有β-桶的外膜蛋白 (OMP) 是由BAM复合体组装在一起的.
- BAM复合体包括必不可少的成分Bama和BamD,以及非必不可少的脂蛋白BamBCE.
研究的目的:
- 研究BamD在外膜蛋白组合和OM完整性中的调节作用.
- 为了阐明在没有BamD的情况下OM破裂背后的机制.
- 识别抑制突变并了解它们对OM稳定性和细胞形状的影响.
主要方法:
- 在bamA中产生功能获取突变,使其能够在没有BamD的情况下生存.
- 观察OM的减弱,细胞形状的改变,以及消耗的介质中的破裂.
- 分析脂翻转和从外侧小册子上去除.
- 识别可以防止OM破裂的抑制器突变.
主要成果:
- 丢失BamD导致OMP的全球减少,削弱OM并导致断裂.
- 脂 (PLs) 翻转到外侧的说明书中,以弥补OMP的损失.
- 膜破裂与PL从外侧小册子上移除后产生的张力有关.
- 抑制器突变阻止了PL的去除,防止了破裂,但不能恢复OM的刚性或细胞形状.
结论:
- BamD的基本功能是监管,影响OMP组装和OM完整性.
- OM的减弱和破裂是OMP损失和随后的脂动态的后果.
- 在OM刚性,脂分布和细菌细胞形状之间存在联系.
相关概念视频
Destabilization of Microtubules
2.8K
The destabilization of microtubules can occur during different stages of the microtubule lifecycle, such as nucleation or elongation. It can take place at either end of the microtubule or in the microtubule lattices as a whole. The lifespan of individual microtubules within a cell varies according to the cell type and stage of the cell cycle. During interphase, the lifespan of the microtubule is about 30 minutes, while during cell division, it is about 15 minutes. In axonal microtubules of...
2.8K
Export of Misfolded Proteins out of the ER
3.6K
After folding, the ER assesses the quality of secretory and membrane proteins. The correctly folded proteins are cleared by the calnexin cycle for transport to their final destination, while misfolded proteins are held back in the ER lumen. The ER chaperones attempt to unfold and refold the misfolded proteins but sometimes fail to achieve the correct native conformation. Such terminally misfolded proteins are then exported to the cytosol by ER-associated degradation or ERAD pathway for...
3.6K
The Proteasome
8.8K
Eukaryotic cells can degrade proteins through several pathways. One of the most important amongst these is the ubiquitin-proteasome pathway. It helps the cell eliminate the misfolded, damaged, or unwarranted cytoplasmic proteins in a highly specific manner.
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. A series of enzymes carry out the ubiquitination of the target proteins - E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3...
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. A series of enzymes carry out the ubiquitination of the target proteins - E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3...
8.8K
Regulated Protein Degradation
7.4K
It is vital to regulate the activity of enzymatic as well as non-enzymatic proteins inside the cell. This can be achieved either through creating a balance between their rate of synthesis and degradation or regulating the intrinsic activity of the protein. Both these regulation mechanisms play an essential role in the normal functioning of cells.
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...
7.4K
Protein Denaturation
4.3K
The function of proteins depends on their native three-dimensional structure, which is dictated by the amino acid sequence of the specific protein. Folding of the polypeptide chain takes place under specific conditions that energetically favor the folded conformation. In contrast, protein denaturation occurs spontaneously under unfavorable conditions that disrupt the integrity of the folded conformation. Thus, the chemical and physical environment of a protein, such as significant changes in pH...
4.3K
Protein Modifications in the RER
5.2K
Modification of secretory and transmembrane proteins entering the rough ER begins in the ER lumen. These modifications aid in protein folding and stabilize the acquired tertiary structure. Protein modifications in the rough ER co-occur at different stages of protein folding.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal...
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal...
5.2K


