REGULATION OF ZYMOGEN GRANULE K+ TRANSPORT/EXOCYTOSIS

受调节的胞吐作用是细胞响应于胞吐作用的过程。 通过将储存的产物释放到细胞外， 通过分泌颗粒与血浆的融合， 膜的 胞吐作用是消化，唾液分泌， 肺维护、内分泌释放和突触传递。 一 该系统的特定故障是导致病理学的原因 与囊性纤维化有关 为了理解和纠正 对于胞吐作用的干扰，必须首先阐明其基本机制。 该提议使用良好表征的大鼠胰腺作为模型， 旨在阐明分泌颗粒电解质 转运和胞吐膜融合。 这些分泌颗粒 含有Cl-和K+通道，当 激活 具体而言，该项目将确定机制 负责激活胰腺中的KATP通道 酶原颗粒沿着这些颗粒离子的生理作用 渠道 使用分离的酶原颗粒，KATP通道将 检查电生理学和G蛋白偶联途径， 激活将被证明。 待测试的模型提出， 颗粒KATP通道负责控制净颗粒盐 运输和肿胀。 使用膜融合的体外测定， 这一颗粒通道的激活和净溶质运输，将是 显示有助于胞吐事件的效率或速率。 实验将进一步区分颗粒运输 对初始熔合孔的形成有直接贡献 或者通过简单地使微观孔进入整个膜 通过连接的扩大和稳定而融合。

Regulated exocytosis is the process whereby a cell responds to a physiological signal by releasing a stored product into the extracellular environment through the fusion of secretory granules with the plasma membrane. Exocytosis is fundamental to digestion, salivary secretion, lung maintenance, endocrine release, and synaptic transmission. A specific failure of this system is responsible for the pathology associated with cystic fibrosis. In order to understand and rectify disturbances of exocytosis, the basic mechanism must first be clarified. This proposal uses the well characterized rat pancreas as a model, and is designed to elucidate a coupling between secretory granule electrolyte transport and exocytotic membrane fusion. These secretory granules contain Cl-and K+ channels that are capable of net salt transport when activated. Specifically, the project will determine the mechanism responsible for the activation of the KATP channel in the pancreatic zymogen granule along with the physiological role of these granule ion channels. Using isolated zymogen granules, the KATP channel will be examined electrophysiologically and a G-protein coupled route to activation will be demonstrated. The model to be tested proposes that the granule KATP channel is responsible for controlling net granule salt transport and swelling. Using in vitro assays for membrane fusion, the activation of this granule channel, and net solute transport, will be shown to contribute to the efficiency or rate of the exocytotic event. The experiments will further differentiate between granule transport having a direct contribution to the formation of the initial fusion pore or by simply causing the microscopic pore to proceed to full membrane fusion via the widening and stabilizing of the connection.