細胞カルシウムの混乱は,光のERタンパク質の分泌を誘発する
Cell
|November 17, 1989
まとめ
カルシウムイオノフォアは,ネズミの線維芽細胞からの内プラズマ網膜 (ER) レチキュロプラズミンの分泌を誘発する. このカルシウム誘発の分泌は,ERタンパク質の保持を妨げ,カルシウムを強調します.
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.
- バイオケミストリー バイオケミストリー
背景:
- エンドプラズマ網膜 (ER) は,通常,ER内に留まり,分泌経路から除外される,レチキュロプラズミンと呼ばれる光のタンパク質を収容しています.
- ERタンパク質の保持を制御するメカニズムを理解することは,細胞の恒常性およびタンパク質の密輸に不可欠です.
研究 の 目的:
- カルシウムイオノフォールがネズミの線維芽細胞からのレチキュロプラズミンの分泌に及ぼす影響を調査する.
- ER内のレチキュロプラズミンの保持と分類における細胞カルシウム濃度の役割を明らかにする.
主な方法:
- マウリン線維芽細胞のカルシウムイオノフォアの治療.
- ゼルの移動性とエンドグリコシダゼHの感受性を用いて分泌および細胞内エンドプラズミンの形態の分析.
- ER構造とタンパク質分布の顕微鏡検査.
主要な成果:
- カルシウムイオノフォア処理により,レチキュロプラズミンの効率的な分泌が誘発された.
- 分泌および細胞内プラズミンは,異なるゲル移動性とエンドグリコシダゼHの感受性を示した.
- レチキュロプラズミンの分泌は,ERの枯渇とゴルギの蓄積をもたらした.
- カルシウムイオノフォールに対するERストレス反応は,レチキュロプラズミンの再蓄積と抑制された分泌につながった.
- ERの構造と分布は,分泌の過程で変化した.
結論:
- 細胞カルシウム濃度の乱れは,レチキュロプラズミンのER保持機構を乱します.
- カルシウムイオンは,レチキュロプラズミンが分泌タンパク質から分離する際に重要な役割を果たしている可能性が高い.
- この発見は,ERにおけるカルシウムシグナル伝達とタンパク質密輸の間のダイナミックな相互作用を示唆している.
関連する概念動画
01:17Role of ER in the Secretory Pathway
Eukaryotic cells have a special pathway that enables communication between various intracellular membrane-bound compartments and also with the extracellular environment. This pathway is termed as the secretory pathway.
Components of the secretory pathway
About a third of proteins synthesized in the cell are sorted via the secretory route. They shuffle between different compartments in membrane-bound vesicles until they reach their final destination. The main intracellular compartments involved...
Components of the secretory pathway
About a third of proteins synthesized in the cell are sorted via the secretory route. They shuffle between different compartments in membrane-bound vesicles until they reach their final destination. The main intracellular compartments involved...
01:37The 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...
01:31Regulation 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...
01:28Assembly of the Lipid Bilayer in the ER
Biological membranes are more than just a barrier separating cell cytoplasm from the outside environment. They are highly dynamic and help maintain the integrity and physiological stability of the cells as well as membrane-bound organelles. Membranes also play vital roles in cell-to-cell and intracellular communication.
A large chunk of any biological membrane is composed of phospholipids. These lipids have a heterogeneous distribution across different subcellular organelles and even between...
A large chunk of any biological membrane is composed of phospholipids. These lipids have a heterogeneous distribution across different subcellular organelles and even between...
01:27Feedback Regulation of Calcium Concentration
Calcium is an essential signaling molecule required for various cellular functions. Calcium pumps and ion channels on cell and organellar membranes, such as those on the endoplasmic reticulum (ER), regulate calcium concentrations inside the cell. They remain closed, keeping the cytosolic calcium levels low at a resting state.
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
01:16Calmodulin-dependent Signaling
Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...