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Updated: Jul 15, 2026

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Optimized Protocol for the Extraction of Proteins from the Human Mitral Valve
Published on: June 14, 2017
ミトコンドリアタンパク質の輸入: 処理ペプチダゼと,タンパク質を強化する処理であるPEPの識別
G Hawlitschek1, H Schneider, B Schmidt
1Institut für Physiologische Chemie, Physikalische Biochemie und Zellbiologie, Universität München, Munich, Federal Republic of Germany.
Cell
|June 3, 1988
まとめ
研究者は,ミトコンドリアのタンパク質輸送に不可欠な2つのタンパク質,マトリックス処理ペプチダゼ (MPP) と処理強化タンパク質 (PEP) を特定しました. 組み合わせた作用により,重要なタンパク質分解分裂を回復させ,新しいミトコンドリア信号ペプチダゼを明らかにします.
科学分野:
- ミトコンドリア生物学 ミトコンドリア生物学
- タンパク質の輸送
- バイオケミストリー バイオケミストリー
背景:
- 核でコードされたタンパク質は,ミトコンドリアインポートのためのターゲティング配列を必要とします.
- これらの配列のタンパク質分解分裂は,ミトコンドリアマトリックスで起こります.
- この処理を理解することは,ミトコンドリアの機能の鍵です.
研究 の 目的:
- ミトコンドリア前駆体タンパク質の処理を担当する酵素を分離し,特徴づけること.
- このタンパク質分解活動における個々の成分の役割を解明する.
- この酵素を他の既知のシグナルペプチダゼと比較するために.
主な方法:
- Neurospora crassaミトコンドリアからの処理活動の分離と浄化.
- 孤立したタンパク質成分の生化学的特徴.
- 再構成検査は,機能的相互作用を決定する.
主要な成果:
- 2つのタンパク質複合体であるマトリックス処理ペプチダゼ (MPP) と処理強化タンパク質 (PEP) を精製した.
- MPPは触媒活性を持ち,PEPはその活性を増強する.
- 組み合わせたMPP-PEP複合体は完全な処理活動を回復させ,新しい信号ペプチダゼを示唆する.
結論:
- ミトコンドリア前駆体タンパク質の処理には,二重の酵素系が含まれています.
- MPPは触媒のサブユニットであり,PEPは重要な強化剤として作用する.
- このシステムは,細菌およびERの同類と比較して,異なるシグナルペプチダースのクラスを表しています.
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...
Protein Import into the Peroxisomes
Cells contain membrane-bound organelles called peroxisomes that oxidize organic molecules by transferring hydrogen atoms to oxygen, producing hydrogen peroxide. Peroxisomes enzymatically convert the released hydrogen peroxide into water and oxygen.
Peroxisomal Protein Import:
Peroxisomes lack the genetic machinery required to code for their own proteins. Hence, most peroxisomal membrane, lumenal and transmembrane proteins are synthesized in the cytoplasm or ER and transported to the peroxisome...
Peroxisomal Protein Import:
Peroxisomes lack the genetic machinery required to code for their own proteins. Hence, most peroxisomal membrane, lumenal and transmembrane proteins are synthesized in the cytoplasm or ER and transported to the peroxisome...

