細胞およびミトコンドリアのチオレドキシンによる制御されたタンパク質デニトロシル化
Moran Benhar1, Michael T Forrester, Douglas T Hess
1Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.
まとめ
チオレドキシン酵素は,重要な細胞シグナル伝達プロセスであるタンパク質デニトロシル化を調節する. この研究では,チオレドキシン-1とチオレドキシン-2が,細胞信号伝達とアポトーシスに影響を与えるカスパース-3の重要なデニトロシルアゼであると特定しています.
科学分野:
- バイオケミストリー バイオケミストリー
- セルラー・シグナリング
- 分子生物学は分子生物学である.
背景:
- 酸化窒素 (NO) は,システイン残基のS-ニトロシル化による細胞信号伝導に不可欠です.
- タンパク質デニトロシル化,つまりNO変異の除去を制御するメカニズムは,細胞シグナル伝達においてほとんど知られていない.
- デニトロシラーゼの活性を理解することは,NO媒介の細胞過程の解明に不可欠です.
研究 の 目的:
- タンパク質のデニトロシル化に起因する酵素活動を特定する.
- カスパース-3を調節する特定のデニトロシルアゼの役割を調査する.
- 基礎および刺激誘発タンパク質デニトロシル化のメカニズムを探求する.
主な方法:
- デニトロシラーゼの活性性を特定するための生化学的スクリーニング.
- デニトロシル化のためのモデル基質としてのカスパース-3にフォーカスします.
- 人間のリンパ球とFas刺激を用いて,細胞の反応を研究する.
- チオレドキシン-チオレドキシン・リドゥクタゼの抑制により,基板を特定する.
主要な成果:
- チオレドキシンとチオレドキシン還元酵素は,デニトロシラーゼ活動として特定されました.
- ティオレドキシン-1のデニトロシル化型細胞性カスパース-3は,静止リンパ球で,低S-ニトロシル化を維持する.
- ティオレドキシン-2は,Fas刺激時にミトコンドリア関連カスパース-3のデニトロシル化を媒介し,活性化とアポトーシスを促進する.
- 抑制試験では,内生性S-ニトロシル化の追加の基質が明らかになった.
結論:
- 特定のチオレドキシン酵素 (チオレドキシン-1とチオレドキシン-2) はデニトロシルゼとして作用する.
- これらの酵素は,カスパーゼ-3の基礎および刺激誘発S-ニトロシル化を調節する際,異なる役割を果たします.
- ティオレドキシン系は,哺乳類の細胞におけるタンパク質デニトロシル化を制御し,細胞シグナル伝達とアポトーシスに影響を与える上で極めて重要です.
関連する概念動画
Protein Modifications in the RER
Modification of secretory and transmembrane proteins entering the rough ER begins in the ER lumen. These modifications aid in protein folding and stabilize the acquired tertiary structure. Protein modifications in the rough ER co-occur at different stages of protein folding.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
Covalently Linked Protein Regulators
Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.
These groups modify specific amino acids in a protein.
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,...
Regulation of Nuclear Protein Sorting
Nuclear protein sorting regulates nucleus composition and gene expression, crucial for determining the fate of a eukaryotic cell. Hence, the entry and exit of molecules across the nuclear envelope is a tightly controlled process. Nuclear protein sorting can be inhibited by one of the following ways: 1) masking cargo signal sequences, 2) modifying the nuclear receptor's affinity for cargo, 3) controlling the nuclear pore size, 4) retaining the cargo during its transit to the cytosol or the...
The Electron Transport Chain
The electron transport chain or oxidative phosphorylation is an exothermic process in which free energy released during electron transfer reactions is coupled to ATP synthesis. This process is a significant source of energy in aerobic cells, and therefore inhibitors of the electron transport chain can be detrimental to the cell's metabolic processes.
Inhibitors of the electron transport chain
Rotenone, a widely used pesticide, prevents electron transfer from Fe-S cluster to ubiquinone or Q in...
Inhibitors of the electron transport chain
Rotenone, a widely used pesticide, prevents electron transfer from Fe-S cluster to ubiquinone or Q in...
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...

