相关实验视频
Updated: Aug 10, 2026

11:36
In Vitro Ubiquitination and Deubiquitination Assays of Nucleosomal Histones
Published on: July 25, 2019
在非lysine 残留物上通过病毒E3 ubiquitin 结合酶进行ubiquitination
1Department of Molecular and Cell Biology, 142 Life Sciences Addition Room 3200, Berkeley, CA 94720, USA.
概括
卡波西的肉瘤相关的疹病毒MIR1 E3结合酶针对MHC I进行降解,即使没有氨酸残留物. 这种新的无处不在化途径涉及氨酸残留物,扩大了我们对蛋白质调节的理解.
科学领域:
- 分子生物学分子生物学
- 病毒学 病毒学
- 细胞生物学 细胞生物学
背景情况:
- 乌比基化是一个关键的细胞过程,调节蛋白质功能,主要由E3乌比基连接酶介导.
- E3 基因酶决定了基质的特异性,并催化了基因和基质氨酸残留物或N端之间形成的异类键.
- 卡波西肉瘤相关的疹病毒编码MIR1和MIR2E3连接酶,参与主要基因相容性复合体I类 (MHC I) 无处不在和内部化.
研究的目的:
- 研究MIR1和MIR2E3酶调节MHC I无化和下调的机制.
- 确定MIR1是否可以在没有可访问的氨酸残留的情况下调解MHC I的泛化和降解.
主要方法:
- 使用了突变的MHC I分子,缺乏细胞内酶残留物.
- 在MIR1和MIR2的存在下,评估了MHC I的无处不在状态.
- 分析了乌比奎丁-MHC I关联对β2-甲乙醇的敏感性.
- 研究了氨酸残留在泛化过程中的作用.
- 采用工程设计的MHC I分子与含有氨酸残留物的人造细胞内质域.
主要成果:
- MIR1,但不是MIR2,诱导了MHC I分子的下调,缺乏细胞内酶残留物.
- 这些缺乏氨酸的MHC I分子由MIR1的ubiquitination对β2-mercaptoethanol敏感,表明非氨酸链接.
- 这种新型的无处不在需要在MHC I细胞内体尾巴中的氨酸残留物.
- 一个工程MHC I分子与人工尾巴中的囊素被MIR1.1内细胞化并降解.
结论:
- MIR1介导一种独特的无处不在的形式,准缺乏可访问的氨酸或N-终端的蛋白质.
- 这种依赖氨酸的无处可见化途径有助于MHC I下调.
- 这些发现扩大了已知的蛋白质无化和病毒E3结合酶调节的机制.
相关概念视频
Covalently Linked Protein Regulators
Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.
These groups modify specific amino acids in a protein.
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...
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...
Intralumenal Vesicles and Multivesicular Bodies
Intraluminal vesicles (ILVs) are small vesicles 50-80 nm in diameter formed during the maturation of early endosomes. A specialized endosome containing numerous ILVs is called a multivesicular body (MVB). ILVs contain internalized molecules such as antigens, nucleic acids, proteins, and metabolites. Some of these molecules are released from the MVBs inside exosomes and are transported to other cells. Other MVBs contain molecules that are retained in the ILVs and are later degraded within the...
Export of Misfolded Proteins out of the ER
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...
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...

