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Roles of Phospholipid Molecular Species in Cell Signaling

磷脂分子种类在细胞信号传导中的作用

基本信息

批准号：
62430023
负责人：
KITO Makoto
金额：
$ 10.5万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1989
项目状态：
已结题

项目摘要

Roles of phospholipid molecular species in cell signaling were studied. Mass changes in the various molecular species of phospholipids were determined after stimulation of human platelets with thrombin and collagen. Upon stimulation, every molecular species of phosphatidylinositol and phosphatidylserine was equally hydrolyzed, whereas the molecular species of phosphatidylcholine and diacyl- and alkenylacyl-phosphatidylethanolazine containing arachidonic acid were selectively hydrolyzed. The Ca^<2+> concentration affects the differential degradation of phospholipid molecular species in activated human platelets.The thromboxane A_2 antagonist, ONO3708, completely inhibited the increase in cytosolic free Ca^<2+> in human platelets during activation with collagen. Half-maximal Ca^<2+> release and influx required about 3 and 4 nM STA_2, a stable thromboxane A_2 mimetic, respectively. However, half-maximal activation of phospholipase C required about 18 nM STA_2.The Ca^<2+> channel blocker, … More nifedipine, a dihydropyridine derivative, inhibited the Ca^<2+> influx and release from internal stores caused by collagen or a low concentration of STA_2 (10 nM), but did not inhibit those caused by thrombin or a high concentration of STA_2 (100 nM). These results indicate the presence of two distinct, dihydropyridine-sensitive and insensitive, Ca^<2+> channels dependent on the concentrations and classes of agonists in human platelets.^<125>I-labeled epidermal growth factor was incorporated into and highly concentrated in endosomes of Chinese hamster V79-UF cells during incubation at 37ﾟC for 8 min after binding to its receptors on the cell surface at 4ﾟC. From the labeled cells, endosomes were isolated by isopyenic centrifugation on a Percoll density gradient and then sucrose density gradients. Endosome membranes were found to differ from plasma membranes in the phospholipid composition. The contents of molecular species of diacylphosphatidyleholine and diacylphosphatidylethanolamine with two monoenoic fatty acids were lower in endosomes than in plasma membranes. The differences in the polar head group and molecular species compositions of phospholipids between endosomes and plasma membranes did not change, regardless of whether or not the proportions of phospholipid molecular species in plasma membranes changed. Less

研究了磷脂分子种类在细胞信号传导中的作用。用凝血酶和胶原蛋白刺激人血小板后，测定了各种磷脂分子的质量变化。在刺激下，磷脂酰肌醇和磷脂酰丝氨酸的每个分子种类均被同等地水解，而含有花生四烯酸的磷脂酰胆碱和二酰基-和烯酰基-磷脂酰乙醇嗪的分子种类被选择性地水解。 Ca 2+ 浓度影响活化的人血小板中磷脂分子种类的差异降解。血栓素A_2拮抗剂ONO3708完全抑制胶原活化过程中人血小板中胞质游离Ca 2+ 的增加。半最大Ca 2+ 释放和流入分别需要约3和4nM STA_2，稳定的血栓素A_2模拟物。然而，磷脂酶 C 的半最大激活需要约 18 nM STA_2。Ca^2+ 通道阻滞剂……硝苯地平（一种二氢吡啶衍生物）可抑制胶原蛋白或低浓度 STA_2 (10 nM) 引起的 Ca^2+ 流入和内部储存释放，但不会抑制凝血酶或高浓度 STA_2 引起的 Ca^2+ 流入和释放。 (100纳米)。这些结果表明，存在两种不同的二氢吡啶敏感和不敏感的 Ca^2+ 通道，具体取决于人血小板中激动剂的浓度和类别。^<125>I 标记的表皮生长因子在与细胞表面的受体结合后，在 37°C 孵育 8 分钟后被掺入中国仓鼠 V79-UF 细胞的内体中并高度浓缩。 4°C。通过在 Percoll 密度梯度上、然后在蔗糖密度梯度上等密度离心，从标记的细胞中分离核内体。发现内体膜与质膜的磷脂成分不同。内体中含有两个单烯脂肪酸的二酰基磷脂酰胆碱和二酰基磷脂酰乙醇胺分子种类的含量低于质膜中的含量。无论质膜中磷脂分子种类的比例是否改变，内体和质膜之间磷脂的极性头基和分子种类组成的差异都没有改变。较少的