Calcium dynamics in secretory granule-containing cells

含分泌颗粒细胞中的钙动态

• 批准号: 7057443
• 负责人: JOSEPH G DUMAN
• 金额: $ 4.83万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-12-01 至 2008-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7057443
• 关键词: calcium flux; cell component structure /function; chromaffin cells; granule; intracellular transport; laboratory rat; neuroendocrine system; postdoctoral investigator; tissue /cell culture

DESCRIPTION (provided by applicant): Ca2+ is a second messenger regulating many vital processes; therefore, cellular mechanisms for inciting, terminating, and shaping Ca2+ signals attract intense research. Ca2+ fluxes between the cytosol and both the extracellular space and the endoplasmic reticulum (ER) are the best-understood components of Ca2+ dynamics. However, other organelles, such as secretory granules (SG), may also contribute. It has long been known that SG maintain Ca2+ levels well above those of the cytosol. Recent work demonstrating the presence of functional release channels and emphasizing the highly localized action of Ca2+ signals further argues that SG represent important components of the cellular Ca2+ signaling ma- chinery. A confounding factor has been that SG transport protons as well as Ca2+; this complicates Ca2+ measurements by affecting Ca2+ reporters and altering SG Ca2+ buffering. The research in this proposal will quantitatively dissect global cellular Ca2+ transport in SG-containing cells, characterize the Ca2+ buffering capacity of SG, and measure the response of SG Ca2+ to cell stimuli while measuring pH effects on reporters and SG buffers. Ca2+ and pH photometry using both chemical probes and genetically-encoded reporters will be used in both intact neuroendocrine cells and isolated SG to achieve these goals. The results will lead to better understanding of Ca2+ dynamics in neuroendocrine cells, as well as in other clinically relevant cells in which SG Ca2+ is potentially important, including pancreatic beta-cells and mast cells.

描述（申请人提供）：Ca 2+是调节许多重要过程的第二信使;因此，激发、终止和塑造Ca 2+信号的细胞机制吸引了大量研究。细胞质与细胞外间隙和内质网（ER）之间的Ca 2+通量是Ca 2+动力学的最佳理解组分。然而，其他细胞器，例如分泌颗粒（SG）也可能有贡献。长期以来，人们一直知道，SG保持Ca 2+水平远高于那些细胞质。最近的工作表明功能性释放通道的存在，并强调高度局部化的Ca 2+信号的作用，进一步认为SG代表细胞Ca 2+信号机制的重要组成部分。一个混杂因素是SG转运质子以及Ca 2 +;这通过影响Ca 2+报告分子和改变SG Ca 2+缓冲而使Ca 2+测量复杂化。本研究将定量分析含SG细胞中的整体细胞Ca 2+转运，表征SG的Ca 2+缓冲能力，并测量SG Ca 2+对细胞刺激的响应，同时测量pH对报告基因和SG缓冲液的影响。使用化学探针和遗传编码报告基因的Ca 2+和pH光度法将用于完整的神经内分泌细胞和分离的SG以实现这些目标。结果将导致更好地理解神经内分泌细胞中的Ca 2+动力学，以及在其他临床相关细胞中，SG Ca 2+可能是重要的，包括胰腺β细胞和肥大细胞。