ATPに依存した蓄積と,イノシトール三酸塩または循環型ADPリボースによるCa2+の核包膜からの放出
O V Gerasimenko1, J V Gerasimenko, A V Tepikin
1Physiological Laboratory, University of Liverpool, England.
Cell
|February 10, 1995
まとめ
肝臓の核におけるカルシウム (Ca2+) の吸収と放出は,核プラズマではなく,核膜で起こります. イノシトール1,4,5-トリスホスファート (IP3) は,これらの貯蔵庫から核プラズマにCa2+の放出を誘発する.
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:
- カルシウムイオン (Ca2+) は,細胞シグナル伝達と核機能において重要な役割を果たします.
- 以前の研究では,ATPに依存したCa2+吸収と,孤立した核におけるイノシトール1,4,5-トリスホスファート (IP3) 媒介による放出を示していた.
研究 の 目的:
- 孤立した肝臓核内のCa2+輸送の正確な位置とメカニズムを解明する.
- 核包膜によるCa2+の取り扱いと,核プラズマによるCa2+の取り扱いを区別する.
主な方法:
- デジタル画像とコンフォカル顕微鏡を用いた光Ca2+プローブ (フーラ2,カルシウムグリーン1) を利用しました.
- エンドプラズマ網膜のマーカーを使用して,探査機の位置を評価しました.
- 核Ca2+ダイナミクスに対するATP,IP3,および周期性ADP-リボースの影響を調査した.
主要な成果:
- Ca2+ 感受性探査機 Fura 2 は核封筒に定着し,エンドプラズマ網膜のマーカー分布を反映した.
- ATP依存のCa2+吸収とIP3誘発の放出は,核膜ではなく核膜に起因している.
- 核プラズマのCa2+レベルは,外部のCa2+変化を素早く反映し,IP3と周期的なADP-リボースは一時的な核内Ca2+上昇を誘導した.
結論:
- 孤立した肝臓核におけるCa2+輸送は,主に核包膜によって媒介されます.
- 核封筒貯蔵庫からの放出は,核プラズマに導かれ,その後,核の毛穴を通って拡散します.
- これは,核Ca2+シグナル伝達経路の空間的調節を明確にします.
関連する概念動画
01:08Hydrolysis of ATP
The bonds of adenosine triphosphate (ATP) can be broken through the addition of water, releasing one or two phosphate groups in an exergonic process called hydrolysis. This reaction liberates the energy in the bonds for use in the cell—for instance, to synthesize proteins from amino acids.
If one phosphate group is removed, a molecule of ADP—adenosine diphosphate—remains, along with inorganic phosphate. ADP can be further hydrolyzed to AMP—adenosine monophosphate—by the removal of a second...
If one phosphate group is removed, a molecule of ADP—adenosine diphosphate—remains, along with inorganic phosphate. ADP can be further hydrolyzed to AMP—adenosine monophosphate—by the removal of a second...
01:48ATP Synthase: Mechanism
In animals, the mitochondrial F1F0 ATP synthase is the key protein that synthesizes ATP molecules through a complex catalytic mechanism. While the nuclear genome encodes the majority of ATP synthase subunits, the mitochondrial genome encodes some of the enzyme's most critical components. The formation of this multi-subunit enzyme is a complex multi-step process regulated at the level of transcription, translation, and assembly. Defects in one or more of these steps can result in decreased ATP...
01:42The ADP/ATP Carrier Protein
ADP/ATP carrier or AAC protein is the most abundant carrier protein in the inner mitochondrial membrane. It transports large quantities of ADP and ATP, equivalent to the average human body weight, every day. Among other transporters, ACC protein is one of the best-studied members of the mitochondrial carrier protein family. The ADP/ATP carrier protein comprises two transmembrane helices connected to a loop and a single alpha-helix on the matrix side. It switches between two conformational...
01:31ATP Energy Storage and Release
ATP is a highly unstable molecule. Unless quickly used to perform work, ATP spontaneously dissociates into ADP and inorganic phosphate (Pi), and the free energy released during this process is lost as heat. The energy released by ATP hydrolysis is used to perform work inside the cell and depends on a strategy called energy coupling. Cells couple the exergonic reaction of ATP hydrolysis with endergonic reactions, allowing them to proceed.
One example of energy coupling using ATP involves a...
One example of energy coupling using ATP involves a...
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...
01:31ATP Energy Storage and Release
ATP is a highly unstable molecule. Unless quickly used to perform work, ATP spontaneously dissociates into ADP and inorganic phosphate (Pi), and the free energy released during this process is lost as heat. The energy released by ATP hydrolysis is used to perform work inside the cell and depends on a strategy called energy coupling. Cells couple the exergonic reaction of ATP hydrolysis with endergonic reactions, allowing them to proceed.
One example of energy coupling using ATP involves a...
One example of energy coupling using ATP involves a...