関連する実験動画
Updated: Aug 9, 2026

05:52
Reconstitution of Msp1 Extraction Activity with Fully Purified Components
Published on: August 10, 2021
前体タンパク質の認識と膜挿入に必要なミトコンドリア受容体複合体の特定
Nature
|December 13, 1990
まとめ
ミトコンドリアインポート受容体MOM19とMOM72は,MOM38とMOM22と共に,前駆体タンパク質インポートのための複合体を形成する. MOM38は,一般的な挿入部位 (GIP) の重要な構成要素として特定されています.
科学分野:
- ミトコンドリアバイオゲネシスとタンパク質輸入経路.
- タンパク質が臓器膜を横断して転位する分子機構.
背景:
- ミトコンドリアの機能には精密なタンパク質の輸入が必要です.
- 外部ミトコンドリア膜受容体は,前駆体タンパク質の認識と転位を媒介する.
研究 の 目的:
- ミトコンドリアタンパク質輸入受容体複合体の構成と機能を明らかにする.
- タンパク質の輸入におけるMOM19,MOM72,MOM38,MOM22の特定の役割を特定する.
主な方法:
- ミトコンドリア外膜内のタンパク質-タンパク質相互作用の生化学分析.
- 先駆体タンパク質転位における特定された受容体複合体の機能の特徴化.
主要な成果:
- ミトコンドリアインポート受容体MOM19とMOM72は,MOM38とMOM22と安定した複合体を形成する.
- MOM38は,タンパク質の挿入に不可欠な一般的な挿入部位 (GIP) の構成要素として特定されました.
- この複合体は,前駆体タンパク質の認識,膜挿入,転位を促進します.
結論:
- MOM19/MOM72/MOM38/MOM22複合体は,効率的なミトコンドリアタンパク質輸入に不可欠である.
- MOM38は,GIP経由の膜挿入段階において重要な役割を果たします.
関連する概念動画
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...
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...
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,...
Porin Insertion in the Outer Mitochondrial Membrane
Porins are beta-barrel proteins translocated to the mitochondrial outer membrane through the TOM complex into the intermembrane space. Porin precursors bind TIM chaperones within the intermembrane space and are guided to the Sorting and Assembly Machinery complex or SAM complex on the outer mitochondrial membrane.
Three models describe the assembly of porins by the SAM complex and their insertion into the outer membrane. Model 1 suggests that porins are assembled outside the SAM channel as the...
Three models describe the assembly of porins by the SAM complex and their insertion into the outer membrane. Model 1 suggests that porins are assembled outside the SAM channel as the...
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...
Structure of Porins
Mitochondria, chloroplasts, and gram-negative bacteria have transmembrane, beta-barrel proteins called porins to mediate the free diffusion of ions and metabolites across the membrane. Mitochondrial porin precursors contain conserved amino acid sequences called beta signals at their C-terminal. Beta signals have a motif of PoXGXXHyXHy (Po-Polar, X-Any amino acid, G-Glycine, Hy-LargeHydrophobic), which are crucial for precursor recognition to initiate precursor assembly. Beta-barrel precursors...

