関連する実験動画
Updated: May 21, 2026

09:01
Measurement of Protein Import Capacity of Skeletal Muscle Mitochondria
Published on: January 7, 2022
ATFS-1のミトコンドリア輸入効率は,ミトコンドリアのUPR活性化を調節する
Amrita M Nargund1, Mark W Pellegrino, Christopher J Fiorese
1Cell Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
まとめ
細胞は,ATFS-1タンパク質のミトコンドリアへの輸入を調節することによって,ミトコンドリアのストレスを感知します. 輸入量の減少により,ATFS-1が核に信号を送り,保護反応を活性化させることができます.
科学分野:
- 細胞生物学 細胞生物学
- 分子生物学は分子生物学である.
- 遺伝学 遺伝学とは
背景:
- ミトコンドリア機能障害は,細胞のストレス反応を引き起こします.
- ミトコンドリアの展開タンパク質応答 (UPR) は,細胞をミトコンドリアの損傷から保護する.
- ATFS-1 (ストレス-1に関連するトランスクリプション因子活性化) は,UPRの重要な調節体である.
研究 の 目的:
- ATFS-1がミトコンドリアのストレスを感知するメカニズムを解明する.
- ATFS-1がミトコンドリアのストレスを核に伝達する方法を理解するために.
- UPRの規制におけるATFS-1の輸入効率の役割を調査する.
主な方法:
- Caenorhabditis elegansにおけるATFS-1の調節を研究した.
- 試験されたATFS-1ミトコンドリアインポート効率は,正常条件とストレス条件下.
- ATFS-1のN端ミトコンドリア標的配列の役割を評価した.
主要な成果:
- ミトコンドリアへのATFS-1の輸入は,ミトコンドリアのストレスによって調節されます.
- ATFS-1のミトコンドリアインポート効率の低下は,細胞溶液に蓄積することにつながります.
- サイトソリックATFS-1は核に転位し,UPRを活性化します.
結論:
- ATFS-1のミトコンドリア輸入効率は,UPRの重要な規制ポイントである.
- 細胞はATFS-1を制御することで,ミトコンドリアの健康を監視する.
- このメカニズムは,ミトコンドリア機能障害に対する細胞の反応を調整する.
関連する概念動画
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,...
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 precursors...
Most of the mitochondrial precursors...
Energy to Drive Translocation
Mitochondrial protein import is powered by two distinct energy sources: ATP hydrolysis and electrochemical potential across the inner membrane. Newly synthesized precursors are bound by cytosolic chaperones of the Hsp70 family, which guide them to the import receptors on the mitochondrial surface. Utilizing the energy of ATP hydrolysis, Hsp70 chaperones transfer these precursors to the TOM receptors on the mitochondrial outer membrane.
Generally, polypeptides are unfolded by two distinct...
Generally, polypeptides are unfolded by two distinct...
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...
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...
Most of these mitochondrial proteins are encoded by the nucleus and imported to the mitochondria as unfolded or loosely folded precursors. Mitochondrial precursors...
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...

