ANALYSIS OF CARDIAC GLYCOSIDE AFFINITY IN CULTURED CELLS

Na，K泵（即，Na，K-ATPase）被认为是主要的 洋地黄如哇巴因的药理学受体。 这是一 从细胞中挤出Na+的内在膜蛋白复合物 并从外部吸收K+， 能源 它的周转和由此产生的电化学梯度 是造成等离子体间电位差的原因 膜和间接介导离子平衡，细胞体积， 盐和水的上皮运输。 钠钾泵 抑制强心苷，并有变化， 哇巴因在组织之间的亲和力可以高达500倍。 这种变化的基础还不清楚， 该项目将测试假设，哇巴因的变化， Na，K泵的亲和力是由细胞特异性的 其组成亚基的不同同种型的表达。 的 亚基组成和表达的哇巴因亲和力将被 通过RNA杂交在许多培养的细胞系中检测 分析和酶测定，以将特异性 具有给定结合亲和力的同种型。 DNA介导基因转移 将用于将同种型引入受体细胞系 直接观察它们对哇巴因亲和力的影响。 从这些 哇巴因组织变异性的分子基础 将阐明亲和力。 为了完成这个项目，候选人将利用一个 广泛的背景，包括比较生物化学， 运输生理学和分子生物学。 RCDA将确保 候选人可以继续这种多学科的方法。 开展工作的部门是 国际公认的运输生理学领域， 提供了一个理想的环境，在其中发展独立的 研究生涯。 它位于一个主要的健康科学中心内， 应进一步促进创新研究的发展， 钠钾泵的功能和调节。

The Na, K-pump (ie., Na, K-ATPase) is thought to be the major pharmacological receptor for digitalis such as ouabain. It is an intrinsic membrane protein complex that extrudes Na+ from the cell and absorbs K+ from the exterior at the expense of metabolic energy. Its turnover and the resulting electrochemical gradients are responsible for the potential difference across the plasma membrane and indirectly mediate ionic balance, cellular volume, and epithelial transport of salts and water. The Na, K-pump is inhibited by cardiac glycosides, and there is variation in the ouabain affinity between tissues that may be as great as 500-fold. The basis for this variability is not well understood, This project will test the hypothesis that the variation in ouabain affinity of the Na, K-pump is caused by the cell-specific expression of different isoforms of its constituent subunits. The subunit composition and the expressed ouabain affinity will be examined in a number of cultured cell lines by RNA hybridization analysis and enzymatic assays to correlate the presence of specific isoforms with a given binding affinity. DNA-mediated gene transfer will be used to introduce the isoforms into recipient cell lines to observe directly their effects on ouabain affinity. From these studies, the molecular basis of the tissue variability in ouabain affinity will be elucidated. To carry out this project, the candidate will take advantage of a broad background that has included comparative biochemistry, transport physiology, and molecular biology. An RCDA will ensure that the candidate can continue this multidisciplinary approach. The department in which the work will be conducted is internationally recognized in the field of transport physiology and provides an ideal environment in which to develop an independent research career. Its location within a major health science center should further stimulate the development of innovative research in the function and regulation of the Na, K-pump.