eIF2α-Pによる持続的な翻訳抑制は,プリオン神経変異を媒介する
Julie A Moreno1, Helois Radford, Diego Peretti
1MRC Toxicology Unit, Hodgkin Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, UK.
Nature
|May 25, 2012
まとめ
プリオン病における持続的なタンパク質の誤折れは,タンパク質合成を停止することにより,ニューロンの死を引き起こす. 神経変性から保護されたタンパク質翻訳率を回復し,マウスの生存率を向上させた.
科学分野:
- 神経科学は神経科学である.
- 分子生物学は分子生物学である.
- 細胞生物学 細胞生物学
背景:
- アルツハイマー病,パーキンソン病,プリオン病などの神経変性疾患は,誤った折りたたまれたタンパク質の蓄積を伴う.
- 展開されたタンパク質応答 (UPR) は,eIF2α-Pによるタンパク質翻訳の停止を含む,誤った折り畳まれたタンパク質に対する細胞防御です.
- UPRの活性化,eIF2α-P,および神経変性との関連は不明である.
研究 の 目的:
- プリオン誘発性神経変性におけるプリオンタンパク質蓄積とeIF2α-Pの役割を調査する.
- プリオン病のモデルにおいて,タンパク質翻訳の回復が神経保護的になるかどうかを判断する.
- 神経退行性障害の翻訳制御を標的とした治療戦略を探求する.
主な方法:
- プリオン病のマウスモデルを利用して,プリオンタンパク質の蓄積とそのタンパク質合成への影響を研究した.
- eIF2α-Pレベルがシナプス機能とニューロン喪失に与える影響を調査した.
- 遺伝子 (GADD34過剰発現,RNA干渉) と薬理学 (salubrinal) のアプローチを用いてeIF2α-Pとタンパク質翻訳を調節した.
主要な成果:
- プリオンタンパク質の蓄積は,eIF2α-Pによる持続的な翻訳抑制につながり,マウスのシナプス機能不全とニューロン喪失を引き起こしました.
- GADD34を過剰に発現させたり,プリオンタンパク質のレベルを低下させたりすると,eIF2α-Pが低下し,タンパク質の翻訳が回復し,シナプス欠陥とニューロンの喪失が回復し,生存率が増加します.
- eIF2α-P脱酸化を阻害し,サルブリンで神経毒性が悪化し,生存率が低下する.
結論:
- eIF2α-Pによる持続的な翻訳抑制は,プリオン病における神経変性の重要なメカニズムである.
- タンパク質翻訳速度を回復することは,神経保護的戦略を提供します.
- 疾患特異的なメカニズムではなく,翻訳制御のような一般的な経路をターゲットにすることで,多様な神経変性疾患の治療に希望があります.
関連する概念動画
Amyloid Fibrils
10.2K
Amyloid fibrils are aggregates of misfolded proteins. Under most circumstances, misfolded proteins are either refolded by chaperone proteins or degraded by the proteasome. However, in the case of a mutation or a disease, these proteins can accumulate to form large clusters and often further assemble to form elongated fibers, called fibrils.
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining,...
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining,...
10.2K
Nonsense-mediated mRNA Decay
9.4K
The Upf proteins that carry out nonsense-mediated decay (NMD) are found in all eukaryotic organisms, including humans. Each protein has an individual role, but they need to work in collaboration. Upf1 is an ATP-dependent RNA helicase that unwinds the RNA helix. Because Upf1 can unwind any RNA, Upf2 and Upf3 are required to help Upf1 discriminate between nonsense and normal mRNAs.
Usually, Upf3 binds to an Exon Junction Complex (EJC) at mRNA splice sites. If a ribosome fully translates the mRNA,...
Usually, Upf3 binds to an Exon Junction Complex (EJC) at mRNA splice sites. If a ribosome fully translates the mRNA,...
9.4K
The Unfolded Protein Response
5.6K
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...
5.6K
Regulation of the Unfolded Protein Response
2.2K
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...
2.2K
Translation
16.8K
Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes the final step in the expression of genes. This process is carried out by ribosomes, complexes of protein and specialized RNA molecules. Ribosomes, transfer RNA (tRNA), and other proteins produce a chain of amino acids—the polypeptide—as the end product of translation.
Translation Produces the Building Blocks of Life
Proteins are...
Translation Produces the Building Blocks of Life
Proteins are...
16.8K
Translational Regulation
877
Translational regulation in prokaryotes ensures efficient protein synthesis by controlling ribosome access to mRNA. This regulation is mediated by secondary RNA structures, including translational riboswitches, RNA thermometers, and small RNAs (sRNAs), which respond to intracellular and environmental signals to modulate gene expression.Translational RiboswitchesRiboswitches in the leader region of mRNAs can regulate translation by altering the accessibility of the Shine-Dalgarno (SD) sequence,...
877


