REGULATION OF INTRACELLULAR CALCIUM IN RENAL CELLS

描述（改编自申请人的摘要）： 感觉细胞中的机械感测和转导早已为人所知。 近年来，很明显， （细胞膨胀、膜拉伸、剪切应力产生的机械应力） 在非感觉细胞中可以在调节许多细胞中起主要作用 包括钙内流和因此的Ca+信号传导的过程。 肾 细胞，生理和病理生理产生的机械应力 已知状态通过所谓的Ca+通道激活Ca+内流， 钙通道阻滞剂（例如， 二氢吡啶类（DHP），L型Ca+通道阻滞剂）。 最近他们 鉴定了一种新的DHP敏感性Ca+通道（Ca+选择性）， 兔近曲小管细胞的边缘似乎起着中心作用 处于机械诱导的Ca+信号状态。 通道被激活 通过细胞膨胀和细胞膜拉伸。 它似乎是受管制的 间接通过磷脂酰肌醇机械敏感性调节 水解（磷脂酶C-b）和激活蛋白激酶C类似于 最近在心肌细胞L型Ca+通道中发现了这一点。 的 该项目的总体目标是描述功能，调节和 这个新渠道的结构有以下四个具体目标：1） 为了确定DHP敏感性Ca+通道在调节 机械应激过程中细胞内钙水平和Ca+信号转导 状态（机械，膜拉伸）; 2）表征通道 DHP敏感性Ca+的特性（单通道和全细胞电流） 通道和机械应力对这些性能的影响; 3） 表征调节细胞凋亡的机械转导途径。 DHP敏感性Ca+通道;和4）为了确定DHP敏感性Ca+通道的分子身份， 近曲小管细胞中的DHP敏感性Ca+通道。 该项目将拥有 广泛的影响，以机械应力的作用，在控制许多 钙在健康和疾病中的依赖功能。

DESCRIPTION (Adapted from the Applicant's Abstract): The importance of mechanical sensing and transduction in sensory cells has long been known. In recent years it has become evident that mechanical stresses (osmo-mechanical stress from cell swelling, membrane stretch, shear stress) in non-sensory cells can play a major role in regulating numerous cell processes including calcium influx and, hence, Ca+ signaling. In kidney cells, mechanical stresses generated by physiological and pathophysiological states are known to activate Ca+ influx through purported Ca+ channels as the influx can be abolished by calcium channel blockers (e.g. Dihydropyridines (DHP), L-type Ca+ channel blocker). Recently they identified a novel DHP-sensitive Ca+ channel (Ca+-selective) on the apical border of rabbit proximal tubule cells that appears to play a central role in mechanically-induced states of Ca+ signaling. The channel is activated by cell swelling and membrane stretch. It appears to be regulated indirectly via mechano-sensitive regulation of phosphatidyl inositol hydrolysis (phospholipase C-b) andactivation of protein kinase C similar to that recently identified for L-type Ca+ channels in cardiac myocytes. The overall goal of the project is to characterize the function, regulation and structure of this novel channel with the following four Specific Aims: 1) To determine the role of the DHP-sensitive Ca+ channel in regulating intracellular calcium levels and Ca+ signaling during mechanically-stressed states (osmo-mechanical, membrane stretch); 2) To characterize the channel properties (single channel and whole cell currents) of the DHP-sensitive Ca+ channel and the effect of mechanical stresses on these properties; 3) To characterize the mechano-transduction pathway(s) regulating the DHP-sensitive Ca+ channel; and 4) To determine the molecular identity of the DHP-sensitive Ca+ channel in proximal tubule cells. The project will have broad implications to the role of mechanical stress in controlling numerous Ca-dependent functions in health and disease.