BKca1CHANNEL REGULATION BY PKG IN VASCULAR SMOOTH MUSCLE

大电导Ca ~（2+）激活的K ~+（BK[Ca]）通道在钙离子通道的调节中起着重要作用。 血管张力，并且它们被认为是血管舒张作用的重要介质， 内皮源性NO和激活cGMP依赖性蛋白的外源性血管扩张剂 激酶（PKG）。在这里，我们建议解决的问题，涉及BK[Ca]通道的激活PKG在血管平滑肌。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是否与渠道稳定关联？PKG介导的BK[Ca] -通道激活是否需要磷酸酶？BK[Ca]通道是否需要平滑肌特异性β 1亚基？蛋白激酶C是否调节PKG对BK通道的作用？在目标2中，我们将集中在PKG的效果的性质，特别是检查其钙依赖性和其对通道的响应，以Ca 2+火花的效果。目的3我们将研究PKGl α的亮氨酸拉链结构域是否是体内PKG介导的Ca 2+触发和BK[Ca]通道开放的调节所必需的。从拟议的工作的结果，预计将促进我们的理解的一个关键的离子通道，调节血管舒缩的调节，他们可能会建议新的策略，用于治疗高血压和缺血性心血管疾病的药物开发。

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.