BETA1 AND BETA2 ADRENOCEPTOR SIGNALING IN CARDIAC MYOCYTE

3肾上腺素受体（pARs）信号转导被精细调节，以控制心血管功能， 交感神经系统输入（去甲肾上腺素）和肾上腺素（肾上腺素）。 在动物心脏中，两种高度同源的pAR（P1 AR和P2 AR）被儿茶酚胺刺激， 增强收缩力和心率。慢性刺激心脏（3AR）的循环升高 儿茶酚胺以及心脏β 1 AR密度降低在临床上与心力衰竭相关。的 GPCR的主要功能是配体结合和G蛋白偶联。然而，具体和 GPCR在体内的多种功能特性涉及结合的动力学受体构象变化 信号复合物中的不同伴侣，以及受体信号复合物在细胞类型中的定位- 具体方式。我们假设去甲肾上腺素和肾上腺素可以激活不同的信号 心肌细胞中β 1 AR和β 2 AR途径。我们选择了新生心肌细胞 分离自PAR基因缺陷小鼠作为模型系统，以研究配体的功能作用， 分化细胞中的受体相互作用。本提案的目标是（1）表征（31 AR和 |新生心肌细胞中不同激动剂的32 AR亚型特异性信号传导，（2）定义细胞和 去甲肾上腺素和肾上腺素刺激下心肌β_1-AR和β_2-AR的生化特性 （3）研究β 1 AR和β 2 AR及其它信号分子在心肌细胞内的分布 在去甲肾上腺素和肾上腺素刺激下，（4）确定受体相互作用 结构域及其靶蛋白，并表征受体信号传导复合物的形成， 激动剂刺激后的稳定性。更好地理解激动剂诱导的PAR构象变化， 信号复合物的组织可以促进新的药物设计， 在治疗各种心血管疾病中的应用。

3 Adrenoceptors (pARs) signaling is finely regulated to control cardiovascular function in response to sympathetic nervous system input (norepinephrine) and to adrenaline (epinephrine) from the adrenal gland. In animal hearts, two highly homologous pARs (P1AR and P2AR) are stimulated by catecholamines to enhance contractility and heart rate. Chronic stimulation of cardiac (3ARs by elevated circulating catecholamines as well as decreased cardiac (31AR density is clinically associated with heart failure. The primary functions attributed to GPCRs are ligand binding and G-protein coupling. However, the specific and diversified functional properties of GPCRs in vivo involve kinetic receptor conformational changes for binding different partners in signaling complexes, and the localization of receptor signaling complexes in cell type- specific manner. We hypothesize that norepinephrine and epinephrine can activate distinct signaling pathways for both (31AR and (32AR in cardiac myocyte. We have chosen the neonatal cardiac myocyte isolated from the PAR gene deficiency mice as a model system to study the functional roles of ligand- receptor interactions in differentiated cells. The goals of this proposal are (1) to characterize (31 AR and |32AR subtype-specific signaling by different agonists in neonatal myocytes, (2) define the cellular and biochemical properties of (31 AR and P2AR under norepinephrine and epinephrine stimulation in cardiac myocytes, (3) to characterize the subcellular distribution of (31ARand (32AR, and other signaling molecules under norepinephrine and epinephrine stimulation in cardiac myocyte, (4) to identify receptor interaction domains and their targeted proteins, and to characterize the receptor signaling complex formation and stability upon agonist stimulation. A better understanding of agonist-induced PAR conformationchange for the organization of signaling complexes may facilitate new drug designs and suggest new clinical applications in treating various cardiovascular diseases.