Rft1催化了与脂质结合的寡糖体在ER膜上的转位
Shuai Chen1,2,3, Cai-Xia Pei4,5, Si Xu1
1Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.
Nature communications
|June 17, 2024
概括
研究人员证实Rft1是负责将Man5GlcNAc2-PP-Dol (M5GN2-PP-Dol) 翻过内细胞网膜的酶. 这解决了长期以来关于蛋白质糖化中的M5GN2-PP-Dol ER翻酶的争议.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 细胞生物学 细胞生物学
背景情况:
- 细胞的N-链糖化开始于ER中的脂质载体上的寡糖组合.
- Man5GlcNAc2-PP-Dol (M5GN2-PP-Dol) 在细胞质面上合成,必须转移到ER光层.
- 在M5GN2-PP-Dol转位中Rft1的作用一直受到争论,因为体内和体外数据相互矛盾.
研究的目的:
- 解决围绕Rft1在M5GN2-PP-Dol转位中的作用的争议.
- 为了生物化学地表征M5GN2-PP-Dol ER翻转酶.
- 为研究M5GN2-PP-Dol转位建立一个复制的体外系统.
主要方法:
- 开发一种用于M5GN2-PP-Dol转位的复制体内试验.
- 净化Rft1蛋白质的纯化.
- 生物化学表征Rft1的酶活性和基质特异性.
- 对rft1∆ (Rft1删除) 现型的分析.
主要成果:
- 纯化的Rft1直接催化M5GN2-PP-Dol在体外两层脂质中转移.
- Rft1对M5GN2-PP-Dol.的基质具有选择性.
- 试管测试结果与体内遗传数据一致,证实了Rft1的飞酶活性.
- 这项研究为Rft1的作用提供了明确的证据.
结论:
- 证实Rft1是M5GN2-PP-Dol ER转酶.这是一个M5GN2-PP-Dol ER转酶.
- 这解决了长达二十年的关于寡糖转移分子机制的争议.
- 这些发现澄清了真核生物N-链接甘化途径的一个关键步骤.
相关概念视频
Protein Translocation Machinery on the ER Membrane
4.6K
The translocon complex situated on the ER membrane is the main gateway for the protein secretory pathway. It facilitates the transport of nascent peptides into the ER lumen and their insertion into the ER membrane.
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the...
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the...
4.6K
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
Insertion of Single-pass Transmembrane Proteins in the RER
6.7K
Integral membrane proteins are proteins adhered to the lipid bilayer of a cell organelle or membrane. They can be of two types: transmembrane integral proteins that span the lipid bilayer and monotopic proteins that are attached to either side of the membrane but do not pass through it.
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...
6.7K
Post-translational Translocation of Proteins to the RER
5.7K
A sizable fraction of proteins destined for ER are first synthesized in the cell cytosol and then transported across the ER membrane–a process called post-translational translocation. Similar to cotranslationally translocated proteins, these proteins also use the Sec translocon complex to enter the ER lumen.
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
5.7K
Directing Proteins to the Rough Endoplasmic Reticulum
7.2K
The organelle-specific signaling sequences direct proteins synthesized in the cytosol to their final destination like ER, mitochondria, peroxisomes, etc. Some of the proteins directed to ER are then trafficked via vesicles to other organelles within the cell or the extracellular environment through the Golgi complex. For example, the rough ER synthesizes soluble proteins for transportation to the lysosomes or secretion out of the cell. It can also synthesize transmembrane proteins that can...
7.2K
Insertion of Multi-pass Transmembrane Proteins in the RER
8.0K
The rough ER membrane synthesizes, assembles, and embeds transmembrane proteins in diverse topologies. These proteins function as transporters or channels and can remain in the ER membrane or are sent to the Golgi complex, lysosome, and cell membrane.
The multipass transmembrane proteins are the type IV integral membrane proteins with multiple topogenic sequences determining their spatial arrangement in the ER membrane. Nearly all multipass proteins lack a cleavable signal sequence and use...
The multipass transmembrane proteins are the type IV integral membrane proteins with multiple topogenic sequences determining their spatial arrangement in the ER membrane. Nearly all multipass proteins lack a cleavable signal sequence and use...
8.0K


