概括
红细胞离子运输蛋白,带III,在合成过程中插入膜. 一个特定的序列指导其插入到内质网膜膜.
科学领域:
- 分子生物学分子生物学
- 细胞生物学 细胞生物学
- 生物化学 生物化学
背景情况:
- 红细胞阳离子运输蛋白,带III,具有复杂的结构,具有水友和疏水域.
- 了解III带在细胞膜中的插入机制对于理解其功能至关重要.
研究的目的:
- 为了研究红细胞离子运输蛋白的体外生物合成和膜插入,带III.
- 确定涉及到带III膜插入的特定机制和序列.
主要方法:
- 利用贫血小鼠的红状腺前体细胞进行信使RNA提取.
- 在实验室中使用无小麦芽和网细胞溶解细胞系统进行了翻译研究,使用狗胰腺显微体.
- 使用同步翻译和内葡萄糖酶H裂变,分析了带III的配翻译插入和糖化.
主要成果:
- 带III被合成并插入到其成熟的配置中的细胞内膜中,并与狗胰腺显微体的共翻译插入.
- 新合成的III带获得了一种高曼诺斯的寡糖体前体,对内葡萄糖酶H敏感.
- 在合成后期添加的微粒仍然允许正常的跨膜插入和糖化,表明没有N端裂.
结论:
- 带III经历了同翻译的插入到内质网膜膜.
- 一个接近第三波段中间的序列很可能指导其插入膜.
- 这项研究阐明了III带膜插入和糖化酶的机制.
相关概念视频
Translocation of Proteins into the Mitochondria
Mitochondrial precursors are translocated to the internal subcompartments via independent mechanisms involving distinct protein machineries called translocases.
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
Protein Transport into the Inner Mitochondrial Membrane
Nuclear encoded mitochondrial precursors are imported to the inner membrane in a multistep process involving two separate translocons, TIM22 and TIM23. TIM23 is a cation-selective pore that remains closed by the N terminal segment of the protein. Negative charges on the TIM23 act as a receptor for the incoming precursor, pulling the positively charged matrix-targeting sequence for peptide insertion and translocation.
Transport of mitochondrial precursors across the TIM23 channel is driven by...
Transport of mitochondrial precursors across the TIM23 channel is driven by...
Cotranslational Protein Translocation
Translocation of proteins across membranes is an ancient process that occurs even in bacteria and archaebacteria. In fact, the components of the translocation machinery are still conserved between prokaryotes and eukaryotes.
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
Insertion of Single-pass Transmembrane Proteins in the RER
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...
Post-translational Translocation of Proteins to the RER
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...
Protein Translocation Machinery on the ER Membrane
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 translocon complex.
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 translocon complex.


