在McdB中,一个不变的C端托介导其与碳素酶体的相互作用和定位功能
Joseph L Basalla1, Maria Ghalmi1, Y Hoang1
1Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109.
Molecular biology of the cell
|June 26, 2024
概括
研究人员在McdB蛋白中确定了一个关键的C端托芬基因,这对于细菌微分区 (BMC) 碳素酶体结合至关重要. 这一发现揭示了McdB适配蛋白协会的共享机制,并突出了凝结物形成的作用.
科学领域:
- 细胞生物学 细胞生物学
- 生物化学 生物化学
- 微生物学 微生物学
背景情况:
- 细菌微分区 (BMC) 是基于蛋白质的细胞器,调节细菌的新陈代谢.
- 碳素体,一种BMC类型,对于自身养性细菌的碳固定至关重要,存在于不同的α和β类型.
- 维持碳素体分布系统 (Mcd),包括McdA和McdB蛋白质,空间调节碳素体的定位.
研究的目的:
- 阐明McdB蛋白质的分子特征,这些蛋白质负责特定的碳素酶体相互作用.
- 为了确定这些相互作用机制是否在α-和β-碳素酶体之间保持.
- 调查McdB蛋白质特性在碳素酶体结合和定位中的作用.
主要方法:
- 通过序列分析识别McdB蛋白质中保存的C终端图案.
- 在体内研究涉及替代McdB的不变的托残留物.
- 在体外实验中评估McdB蛋白质凝结物形成的实验.
主要成果:
- 为了使McdB与α-和β-碳素体结合,需要一个具有不变的托的C终端保护图案.
- 这种托残留物的突变导致了对碳素酶体的同位定位和定位 in vivo 的分级影响.
- 在体内McdB-carboxysome关联的效率与McdB在体内形成凝结物的能力相关.
结论:
- 一个共享的机制控制了McdB适配蛋白与不同类型的碳素酶体结合.
- 蛋白质凝聚物的形成被认为是McdB-carboxysome关联的一个关键因素.
- 这些发现为BMCs和潜在的其他基于蛋白质的细胞器的调节提供了洞察力.
相关概念视频
Translocation of Proteins into the Mitochondria
3.1K
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,...
3.1K
Cotranslational Protein Translocation
7.3K
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...
7.3K
Protein Transport into the Inner Mitochondrial Membrane
3.7K
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...
3.7K
Mitochondrial Protein Sorting
4.3K
Mitochondria are double-membrane organelles of the eukaryotes involved in cellular metabolism, signaling, ATP synthesis, and programmed cell death. Each of these processes requires specific proteins and enzymes that must be correctly sorted to the right mitochondrial subcompartment for the proper functioning of the organelle.
Most of these mitochondrial proteins are encoded by the nucleus and imported to the mitochondria as unfolded or loosely folded precursors. Mitochondrial precursors...
Most of these mitochondrial proteins are encoded by the nucleus and imported to the mitochondria as unfolded or loosely folded precursors. Mitochondrial precursors...
4.3K
Protein Transport to the Thylakoids
2.3K
Thylakoids are membrane-bound sac-like structures within the chloroplast that serve as sites for photosynthesis. Thylakoid lumen contains many electron transport proteins and is enclosed by a thylakoid membrane rich in the light-harvesting complex. Proteins targeted to the thylakoids are transported as precursors and are sorted by the general TOC/TIC import pathway. Once the precursor reaches the stroma, stromal processing peptidases remove their transit signal and expose thylakoid signal...
2.3K
Tail-anchoring of Proteins in the ER Membrane
3.1K
Tail-anchored, or TA, proteins are estimated to make up to 3-5% of membrane proteins found in the eukaryotic cell. Such proteins have a single transmembrane domain located approximately 30 amino acid residues upstream from the C-terminal end. As a result, the signal recognition particle (SRP) cannot guide a TA protein to the ER membrane for cotranslational insertion. Hence, they are integrated into the ER membrane post-translationally using their C-terminal end as the anchor. TA proteins...
3.1K


