相关实验视频

Updated: Mar 18, 2026

Isolation of mRNAs Associated with Yeast Mitochondria to Study Mechanisms of Localized Translation

Isolation of mRNAs Associated with Yeast Mitochondria to Study Mechanisms of Localized Translation

Published on: March 14, 2014

线粒体未折叠蛋白质反应控制矩阵前RNA处理和翻译

Christian Münch, J Wade Harper

|June 29, 2016

概括

线粒体蛋白质的错误折叠会触发人体细胞中的未折叠蛋白质反应 (UPRmt). 这种反应增加了陪伴体,并减少了线粒体转换,维持了蛋白质平衡.

科学领域:

细胞生物学
分子生物学
遗传学

背景情况:

线粒体基因组整合了来自核和线粒体基因组的蛋白质,需要精确的折叠和组装.
线粒体未折叠蛋白反应 (UPRmt) 在C. elegans中感知并响应矩阵蛋白错折.
由于缺乏急性激活触发器,对哺乳动物的UPRmt理解是有限的.

研究的目的:

研究人类细胞中线粒体矩阵蛋白错折的急性细胞反应.
分析UPRmt激活对线粒体翻译和蛋白质折叠负荷的影响.
建立一个剖析哺乳动物UPRmt的框架.

主要方法:

药理上抑制线粒体基质HSP90/TRAP1或LON蛋白酶以诱导UPRmt.
人类细胞的全球转录和蛋白质组分析.
评估线粒体翻译和前RNA处理的功能研究.

主要成果:

人体细胞中的急性UPRmt激活会诱导广泛的核基因表达,包括用于折叠,前RNA处理和翻译的矩阵蛋白.
在UPRmt期间,线粒体转化被迅速和可逆地抑制.
预RNA处理中的缺陷是由于转录抑制和依赖LON的MRPP3循环.

结论:

急性线粒体蛋白折叠压力通过转化抑制激活了伴侣蛋白的可用性增加和蛋白质合成的减少.
在压力下维护线粒体蛋白质稳定性方面,UPRmt起着至关重要的作用.
这项研究为进一步研究哺乳动物的UPRmt机制提供了基础.

更多相关视频

Analysis of Translation Initiation During Stress Conditions by Polysome Profiling

Analysis of Translation Initiation During Stress Conditions by Polysome Profiling

Published on: May 19, 2014

Polysome Fractionation and Analysis of Mammalian Translatomes on a Genome-wide Scale

Polysome Fractionation and Analysis of Mammalian Translatomes on a Genome-wide Scale

Published on: May 17, 2014

相关概念视频

The Unfolded Protein Response

The Unfolded Protein Response

The ER is the hub of protein synthesis in a cell. It has robust systems to quality control protein folding and also for degradation of terminally misfolded proteins. Under normal conditions, a small proportion of misfolded proteins that cannot be salvaged need to be transported to the cytoplasm by the ER-associated degradation or ERAD pathways. However, if the ERAD cannot handle the misfolded proteins, the cell activates the unfolded protein response or UPR to adjust the protein folding...

Regulation of the Unfolded Protein Response

Regulation of the Unfolded Protein Response

Inositol-requiring kinase one or IRE1 is the most conserved eukaryotic unfolded protein response (UPR) receptor. It is a type I transmembrane protein kinase receptor with a distinctive site-specific RNase activity. As the binding mechanics of the misfolded proteins with the N-terminal domain of IRE-1 are unclear, three binding models — direct, indirect, and allosteric -- are proposed for receptor activation. Nevertheless, it is known that once a misfolded protein associates with IRE1, it...

Mitochondrial Precursor Proteins

Mitochondrial Precursor Proteins

Mitochondrial precursors are partially unfolded or loosely folded polypeptide chains. Newly synthesized precursors are inhibited from spontaneously folding into their native conformation by the cytosolic chaperones, heat shock proteins 70 (Hsp70), and mitochondrial import stimulation factors (MSFs). Precursors bound to MSFs are guided to the TOM70-TOM37 receptors, while precursors bound to Hsp70 chaperones are targetted to TOM20-TOM22 receptor complexes.
Most of the mitochondrial...

Mitochondrial Protein Sorting

Mitochondrial Protein Sorting

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...

Translocation of Proteins into the Mitochondria

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,...

Regulation of Expression at Multiple Steps

Regulation of Expression at Multiple Steps

The gene expression in cells is regulated at different stages: (i) transcription, (ii) RNA processing, (iii) RNA localization, and (iv) translation. Transcriptional regulation is mediated by regulatory proteins such as transcription factors, activators, or repressors—these control gene expression by initiating or inhibiting the transcription of genes. Once a precursor or pre-mRNA is produced, it undergoes post-transcriptional modification, including 5' capping, splicing, and the...