FLUID SECRETION IN PAROTID CELLS--SIGNAL TRANSDUCTION

腮腺细胞的液体分泌--信号转导

• 批准号: 6176181
• 负责人: Stephen Paul Soltoff
• 金额: $ 24.85万
• 依托单位: BETH ISRAEL DEACONESS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-05-01 至 2002-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6176181
• 关键词: acinar cell; adenosine triphosphate; biological signal transduction; calcium channel; chloride channels; enzyme activity; enzyme substrate; immunofluorescence technique; ion transport; isozymes; laboratory rat; membrane transport proteins; mitogen activated protein kinase; neurotransmitter receptor; parotid gland; phospholipase D; phosphorylation; potassium channel; protein kinase C; purinergic receptor; receptor binding; receptor expression; saliva; sodium channel; voltage /patch clamp

The broad, long-term objectives of this proposal are to understand on a molecular level the mechanisms by which neurotransmitters promote receptor- mediated alterations of ion transport events involved in saliva formation (fluid secretion) by the parotid acinar cell. The acinar cell secretes an isotonic primary fluid that is modified by athe salivary ductal system, which adds and removes electrolytes. Secretory events are controlled by the release of neurotransmitters, and athe parotid gland receives parasympathetic and sympathetic innervation. The former is believed to regulate fluid secretion, while the latter is involved in the stimulation of exocytosis and amylase release. ATP is costored and coreleased with neurotransmitters. We have demonstrated that extracellular ATP produces effects on ion transport systems similar to those produced by activation of phospholipase C (:LC)-linked receptors, but by a different mechanism--the activation of a ligand (ATP)-gated Ca2+ permeable ion channel that also appears to be the ATP-binding P2Z purinoceptor. Recently we found that the activation of PLC-linked receptors or P2Z receptors stimulates the tyrosine phosphorylation of PKCdelta, a Ca2+-independent isoform of PKC. In addition, activation of the P2Z receptor is blocked by tyrosine kinase inhibitors and is enhanced by activation of protein kinase C (PKC) by phorbol ester, suggesting that the P2Z channel/receptor is modulated by PKC (perhaps PKCdelta) via the stimulation of protein tyrosine kinases. These results and others in the literature suggest that the activation of fluid secretion by neurotransmitters acting on parotid cells involves the phosphorylation of multiple protei ns on tyrosine and other amino acid residues. This is the overall hypothesis that will be examined. We will determine the involvement of protein kinases and phosphatases ina the activation of ion transport systems (the P2Z receptor, the capacitative Ca2+ entry pathway, and tahe Na-K-2CI cotransporter) involved in fluid secretion. In addition, the activation of phospholipase D, which may contribute to the P2Z receptor activation, will be investigated. We also will examine the subcellular localization and redistribution of multiple PKC isoforms when pLC-linked and P2Z receptors are activated in parotid acinar cells. Together, these studies will provide a more complete understanding of biochemical events involved in fluid secretion and saliva formation, and may suggest potential regulatory sites at which therapeutic agents may alter saliva formation in dysfunctional conditions.

该提议的广泛，长期目标是了解 分子水平神经递质促进受体的机制 涉及唾液形成的离子运输事件的介导的变化 （流体分泌）由腮腺腺泡细胞。 腺泡细胞分泌 通过唾液导管系统修饰的等渗主要流体， 增加并去除电解质。 分泌事件由 神经递质的释放，并且呈腮腺接收 副交感神经和同情神经。 据信前者 调节流体分泌，而后者参与刺激 胞吐作用和淀粉酶释放。 ATP被cosed和发行 神经递质。 我们已经证明了细胞外ATP产生 与激活相似的离子传输系统的影响 磷脂酶C（：LC）连接受体，但通过不同的机制 - 配体（ATP）的Ca2+渗透离子通道的激活 似乎是ATP结合P2Z Purinoceptor。 最近我们发现 PLC连接受体或P2Z受体的激活刺激酪氨酸 PKCDELTA的磷酸化，PKC的Ca2+非依赖性同工型。 在 此外，P2Z受体的激活被酪氨酸激酶阻塞 抑制剂，并通过激活蛋白激酶C（PKC）增强 Phorbol酯，表明P2Z通道/受体由PKC调节 （也许是PKCDELTA）通过刺激蛋白酪氨酸激酶。 这些 结果和文献中的其他结果表明流体的激活 作用在腮腺细胞上的神经递质的分泌涉及 多蛋白的磷酸化 NS酪氨酸和其他氨基酸残基。 这是总体 将要研究的假设。 我们将确定参与 蛋白激酶和磷酸酶Ina激活离子转运 系统（P2Z受体，电容CA2+入口途径和TAHE Na-K-2CI共转运蛋白）参与液体分泌。 另外， 磷脂酶D的激活可能有助于P2Z受体 激活将进行研究。 我们还将检查亚细胞 PLC连接时多个PKC同工型的定位和重新分布 P2Z受体在腮腺腺泡细胞中被激活。 在一起，这些 研究将为生化事件提供更完整的了解 参与液体分泌和唾液形成，并可能表明潜力 治疗剂可能改变唾液形成的调节部位 功能失调的条件。