BKca1CHANNEL REGULATION BY PKG IN VASCULAR SMOOTH MUSCLE

大电导钙激活钾(BK[Ca])通道在细胞周期调控中的作用 血管张力，它们被认为是血管扩张作用的重要介质。 内皮源性NO和外源性血管扩张剂激活cGMP依赖蛋白 蛋白激酶(PKG)。在这里，我们建议解决与血管平滑肌中PKG激活BK[Ca]通道有关的问题。在目标1中，我们将解决与PKG激活BK[Ca]通道的生化机制有关的问题。PKG是否稳定地与渠道关联？PKG介导的BK[Ca]通道激活需要磷酸酶吗？BK[Ca]通道的平滑肌特异性β1亚单位是必需的吗？蛋白激酶C是否调节了PKG对BK通道的作用？在目标2中，我们将重点研究PKG效应的性质，特别是它的钙依赖及其对通道对钙电火花反应的影响。在目标3中，我们将研究PKGα的亮氨酸拉链结构域在体内是否需要PKG介导的钙激发和BK[Ca]通道开放的调节。这项拟议工作的结果有望促进我们对调节血管运动的关键离子通道的理解，并可能为治疗高血压和缺血性心血管疾病的药物开发提供新的策略。

Large-conductance Ca2+-activated K+ (BK[Ca]) channels play a critical role in the regulation ofl vascular tone, and they are thought to be important mediators of the vasodilatory effects of endothelial derived NO and exogenous vasodilators that activate the cGMP-dependent protein kinase (PKG). Here we propose to address questions that relate to the BK[Ca] channel's activation by PKG in vascular smooth muscle. In Aim 1 we will address questions having to do with the biochemical mechanism by which the BK[Ca] channel is activated by PKG. Does PKG stably associate with channel? Is a phosphatase required for PKG-mediated BK[Ca] -channel activation? Is the BK[Ca] channel's smooth muscle-specific beta1 subunit required? And does protein kinase C modulate the effect of PKG on the BK channel? In Aim 2 we will focus on the nature of PKG's effect, examining particularly its Ca2+ -dependence and its effect on the response of the channel to a Ca 2+ spark. And in Aim 3 we will examine whether PKGlalpha's leucine zipper domain is required for PKG-mediated modulation of Ca 2+ sparking and BK[Ca] channel opening in vivo. Results from the proposed work are expected to advance our understanding of the regulation of a key ion channel that regulates vasomotion, and they may suggest new strategies for the development of drugs to treat hypertension and ischemic cardiovascular diseases.