アデノシン・ディフォスファートは,インスリン分泌の細胞内調節剤として作用する
C G Nichols1, S L Shyng, A Nestorowicz
1Department of Cell Biology, Washington University School of Medicine, St. Louis, Missouri 63110, USA. cnichols@cellbio.wustl.edu
まとめ
サルフォニル尿素受容体NBF2の変異は,アデノシン三酸塩感受性カリウム (KATP) 経路が代謝変化に反応し,インスリン分泌に影響を与える方法を乱します. 細胞内MgADPは,SUR NBF2.2に結合することで,これらのチャネルを調節する可能性があります.
科学分野:
- バイオケミストリー バイオケミストリー
- 分子生物学は分子生物学である.
- エンドクリノロジー エンドクリノロジー
背景:
- アデノシン三リン酸 (ATP) 感受性カリウム (KATP) チャンネルは,細胞代謝を電気活動と結びつけ,これは臓のインスリン分泌に不可欠です.
- これらのチャネルは,ATPやアデノシン二酸化酸 (ADP) のような細胞内核酸によって調節されます.
研究 の 目的:
- KATPチャネル調節におけるスルフォニル尿素受容体 (SUR) の第2ヌクレオチド結合折り (NBF2) の役割を調査する.
- 特定のSUR変異がチャネル機能とインスリン分泌に与える影響を理解する.
主な方法:
- SUR遺伝子のサイト・ディレクテッド・ミュータゲネシスで,NBF2.2に重点を置いています.
- 様々な核酸濃度および薬理学的薬剤に対する反応として,KATPチャネル活性に関する電気生理学的分析.
- 野生型と変異型チャネルフェノタイプの比較.
主要な成果:
- SUR NBF2の変異により,KATPチャネルはダイアゾキシドで開くが,代謝抑制に対する感受性を失う.
- ハムスターのSURにおける同様の変異は,ATP抑制のアデノシン・ディフォスファート (ADP) 反抗性を低下させた.
- さらにNBF2の変異は,このフェノタイプを複製し,NBF1の同様の変異はMgADPの感受性に影響を与えなかった.
結論:
- SUR NBF2への細胞内MgADP結合は,KATPチャネルのATP阻害に対抗するために重要である.
- SUR NBF2の機能障害は,幼児期の持続的な高インスリン血糖低血糖症に見られるように,インスリン分泌の調節障害につながる可能性があります.
- SUR NBF2とのMgADPの相互作用は,インスリン分泌の重要な規制メカニズムを表しています.
関連する概念動画
Insulin Secretory Vesicles
Insulin secretory vesicles release insulin to stimulate blood glucose uptake and regulate carbohydrate metabolism. When the blood glucose levels increase, glucose enters the pancreatic β-islet cells through glucose transporters. Once inside, glucose is metabolized through glycolysis, the citric acid cycle, and the electron transport chain, producing ATP. This increase in ATP concentration closes ATP-sensitive potassium channels, leading to depolarization of the membrane and the opening of...
cAMP-dependent Protein Kinase Pathways
Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...
Hormones Regulating Blood Glucose
Insulin is released by beta cells of the pancreas when blood glucose levels are high. It facilitates glucose absorption and utilization in insulin-dependent cells with insulin receptors on their plasma membranes. Insulin promotes glucose uptake by increasing the number of glucose transport proteins in the cell membrane, allowing glucose to enter the cell. As a result, glucose utilization and ATP production are enhanced.
In addition to accelerating glucose uptake and utilization, insulin has...
In addition to accelerating glucose uptake and utilization, insulin has...
Glucose Homeostasis: Pancreatic Islets and Insulin Secretion
The pancreatic islets comprising only 1%-2% of the volume are highly vascularized and innervated mini-organs. They contain five endocrine cell types, including β cells that secrete insulin, which is synthesized as a single polypeptide chain, preproinsulin, processed to proinsulin, and finally to insulin and C-peptide. This process is complex and regulated, involving the Golgi complex, the endoplasmic reticulum, and the secretory granules of the β cell.
Insulin and C-peptide are co-secreted in...
Insulin and C-peptide are co-secreted in...
Insulin: The Receptor and Signaling Pathways
Insulin action is mediated through a receptor tyrosine kinase, akin to the IGF-1 receptor. The number of receptors per cell varies significantly, from 40 on erythrocytes to 300,000 on adipocytes and hepatocytes. The insulin receptor consists of linked α/β subunit dimers, forming a heterotetramer glycoprotein with two extracellular α subunits and two β subunits spanning the membrane. The α subunits inhibit the inherent tyrosine kinase activity of the β subunits, but this inhibition is released...
Glucagon-like Receptor Agonists
Incretins include glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), which stimulate insulin secretion post-meals. In type 2 diabetes, GIP's efficacy is reduced, making GLP-1 a viable drug target. GIP originates from preproGIP.
GLP-1, when administered in high doses intravenously, triggers insulin secretion, inhibits glucagon release, slows gastric emptying, reduces food intake, and restores normal insulin secretion. However, its rapid inactivation by the...
GLP-1, when administered in high doses intravenously, triggers insulin secretion, inhibits glucagon release, slows gastric emptying, reduces food intake, and restores normal insulin secretion. However, its rapid inactivation by the...


