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Assays for the Degradation of Misfolded Proteins in Cells
Published on: August 28, 2016
哺乳动物26S蛋白质体在蛋白质降解过程中保持完整
Franziska Kriegenburg1, Michael Seeger, Yasushi Saeki
1Department of Biology, The August Krogh Building, Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark.
Cell
|October 30, 2008
概括
哺乳动物的蛋白质酶会降解多基化蛋白质,而不会分解. 这一发现挑战了26S蛋白酶解离是蛋白质降解所需的观点,支持非解离模型.
科学领域:
- 细胞生物学 细胞生物学
- 生物化学 生物化学
- 蛋白质降解的分子机制
背景情况:
- 26S蛋白酶体是一个大型蛋白质复合体,负责降解无处不在的蛋白质.
- 一个普遍的假设表明,蛋白酶体分裂成20S核心粒子和调节复合体伴随着基质降解.
研究的目的:
- 调查哺乳动物26S蛋白质体对多基化蛋白质的降解是否涉及复杂解离.
- 为了确定26S蛋白质酶体对蛋白质降解的机制.
主要方法:
- 实验使用固定,放射性标记的26S蛋白酶来跟踪降解过程中分单元的释放.
- 蛋白质酶活性测定在不同的蛋白质酶度以评估重组率.
- 非自然化的电泳检测基质依赖蛋白质酶解离.
- 使用epoxomicin进行抑制研究,以探讨自由调节复合物的作用.
主要成果:
- 固定的26S蛋白酶分解了多基化蛋白 (Sic1,c-IAP1) 没有释放子单元.
- 降解速率与蛋白质酶度无关,这与解离-重组模型的预测相矛盾.
- 非自然化的电泳没有揭示基质依赖的26S蛋白酶解离.
- 20S蛋白酶体的抑制没有影响完整的26S蛋白酶体对基质的降解.
结论:
- 哺乳动物的26S蛋白酶可以降解多基化蛋白质而不会解离.
- 这些发现支持一个模型,其中蛋白质降解发生在26S蛋白质组复合体不拆卸的情况下.
- 这挑战了以前关于蛋白质体解离在降解周期中的必要性的假设.
相关概念视频
The Proteasome
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...
The Proteasome
Eukaryotic cells can degrade proteins through several pathways. One of the most important among 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. This involves participation of a series of enzymes including— E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3 (ubiquitin...
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. This involves participation of a series of enzymes including— E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3 (ubiquitin...
The Proteasome
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...
The Proteasome Structure
The ubiquitin-proteasome pathway is a well-known mechanism utilized by eukaryotic cells to remove cytoplasmic proteins that are misfolded, damaged, or no longer needed. In this pathway, the protein that needs to be eliminated undergoes a process called ubiquitination, where a chain of ubiquitin molecules is attached to the 48th lysine residue of the target protein. This ubiquitin modification helps the proteasome distinguish between a target protein and a healthy protein.
The proteasome is an...
The proteasome is an...
Regulated Protein Degradation
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...
Regulated Protein Degradation
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...

