ANALYSIS OF INOSITOL PHOSPHATE METABOLISM IN T LYMPHOCYTES BY HPLC

以确定代谢物的类型、生成时间和 肌醇磷酸(INSP)转化的代谢途径 在T淋巴细胞激活时产生。与T有关的早期事件 细胞受体(TCR)/抗原(Ag)的相互作用是激活一个 肌醇磷脂(InsPL)特异性磷脂酶C(PLC)，与 随之而来的膜磷脂的水解。这条代谢途径 产生一系列INSP，可能通过以下途径参与细胞激活 从细胞内源性或胞外区动员Ca(+2)。一个 一致的证据表明INS(1，4，5)P3代谢可能 在钙(+2)代谢的调节中起着至关重要的作用。INS(1，4，5)P3为 直接参与细胞内钙离子的动员。研究 在血小板和脑组织中进行的研究表明，INS(1，4，5)P3可以 被特定的5-磷酸单酯酶(5PME)或 被3-激酶(3K)磷酸化为Ins(1，3，4，5)P4。INS(1，4)P2显示为 失去生物活性，而Ins(1，3，4，5)P4可能起钙(+2)的作用 动员剂通过打开某些敏感的膜通道。越高 磷酸化的InsP5和InsP6也可能具有生物学意义， 也许是作为细胞间的调节剂。本项目提议 INS(1，4，5)P3在人和小鼠体内代谢的调节 T淋巴细胞对TCR扰动的反应。适用的条件 不同的激活途径也可能同时被触发 给予了特别的关注。这特别是指通过以下方式激活T细胞 在银呈现的情况下，“辅助”细胞随之而来 与“附件”和/或黏附分子的相互作用。激活其他 信号转导机制，如cAMP或cGMP通过适当的配体 (即：前列腺素)也将考虑它们对 Insp异构体的生成。

To determine the type of metabolites, the time of generation and the metabolic pathways of transformation of the inositol phosphates (InsP) produced upon T lymphocyte activation. An early event associated with T cell receptor (TCR) / antigen (Ag) interaction is the activation of an inositol phospholipid (InsPL)-specific phospholipase C (PLC), with consequent hydrolysis of membrane phospholipids. This metabolic pathway produces a series of InsP, which may be involved in cell activation by mobilizing Ca(+2) from either endogenous or extracellular compartments. A consistent amount of evidence indicates that Ins(1,4,5)P3 metabolism may play a crucial role in the regulation of Ca(+2) metabolism. Ins(1,4,5)P3 is directly involved in Ca(+2) mobilization from intracellular stores. Studies performed in platelets and brain tissues demonstrated that Ins(1,4,5)P3 may be hydrolyzed to Ins(1,4)P2 by a specific 5-phosphomonoesterase (5PME) or phosphorylated by a 3-kinase (3K) to Ins(1,3,4,5)P4. Ins(1,4)P2 appears be deprived of biological activity, while Ins(1,3,4,5)P4 may act as a Ca(+2) mobilizer by opening certain sensitive membrane channels. The higher phosphorylated InsP5 and InsP6 may also have biological significance, perhaps acting as intercellular mediators. The present project proposes to investigate the regulation of Ins(1,4,5)P3 metabolism in human and murine T-lymphocytes in response to perturbation of the TCR. Conditions whereby different activation pathways may also be simultaneously triggered will be given special attention. This refers in particular to T cell activation by Ag in the presence of Ag-presenting, "accessory" cells with the consequent interaction with "accessory" and/or adhesion molecules. Activation of other signal transduction mechanisms, such as cAMP or cGMP by proper ligands (i.e.: prostaglandins) will also be considered regarding their effect on the generation of the InsP isomers.