T-type Ca2+ channels and aldosterone secretion

T型Ca2通道与醛固酮分泌

基本信息

批准号：
7184349
负责人：
PAULA Q BARRETT
金额：
$ 32.47万
依托单位：
UNIVERSITY OF VIRGINIA
依托单位国家：
美国
项目类别：
财政年份：
1987
资助国家：
美国
起止时间：
1987-07-01 至 2009-02-28
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): Both heart failure and chronic renal disease induces a state of neurohormonal activation that hastens their progression. Central to these pathophysiologies is the activation of the Renin-Angiotensin system and aldosterone production. Aldosterone production is Ca 2+ dependent and alH low-voltage-activated (LVA), T-type, Ca 2+ channels are the major carriers of Ca 2+ current in the aldosterone producing cell of the zona glomerulosa (AG). Our laboratory has identified the intracellular loop connecting transmembrane domains II and III (II-III loop) on alpha1H channels as an important center for signal integration. CaMKII phosphorylates S1198 to induce a hyperpolarizing shift in the half-activation potential for gating, and GBbeta2ggamma2binds with high-affinity and inhibits aIpha1H channel activity voltage independently. We test the hypothesis that during cell activation the II-III loop recruits these signaling molecules selectively and with high-affinity and thus enables reciprocal channel regulation to contribute functionally to the physiologically actions of Ang II and dopamine, two hormones that exert strong counter-regulatory control of aldosterone production. We use tools of molecular biology, biochemistry, cell biology and electrophysiology to test this hypothesis in the following specific aims: Aim 1: Specifically we will: (1.1) identify the residues on the alpha1H II-III loop that mediate high affinity CaMKII binding, (1.2) determine if this binding dynamically localizes the kinase to the channel during cell stimulation, (1.3) introduce peptides or CaMKII-regulation resistant channels to adrenal zona glomerulosa cells to perturb channel regulation and evaluate the stimulation of aldosterone secretion by Ang II. Aim 2: Specifically we will: (2.1) identify the critical residues on GBeta2 subunits that mediate inhibition of alpha1H whole-cell channel activity and alpha1H II-III loop binding, (2.2) establish if Gbeta2 subunits inhibit ohH channels in the excised patch, (2.3) use RNAi and viral-mediated delivery of channel regulation-deficient Gbeta subunits to cells of the adrenal zona glomerulosa to disrupt channel regulation and evaluate the inhibition of aldosterone secretion by dopamine.

描述（由申请人提供）：心力衰竭和慢性肾脏疾病诱导神经激活的状态，加速其进展。这些病理生理学的核心是肾素 - 血管紧张素系统和醛固酮产生的激活。醛固酮的产生是Ca 2+依赖性的，ALH低压激活（LVA），T型，Ca 2+通道是Zona Glomerulosa（AG）的醛固酮产生细胞中Ca 2+电流的主要载体。我们的实验室已将连接跨膜结构域II和III（II-III环路）（II-III回路）的细胞内环确定为信号整合的重要中心。 CAMKII磷酸化S1198以诱导半激活潜力的超极化转移，而GBBETA2GGAMMA2BIND具有高亲和力的GBBETA2GGAMMA2BIND，并抑制了AIPHA1H通道活性电压。我们检验了以下假设：在细胞激活过程中，II-III循环选择性地募集了这些信号分子，并具有高亲和力，因此使相互通道调节能够在功能上为Ang II和多巴胺的生理作用做出贡献，两种激素，两种激素，具有强大的醛固酮生产的强质控制。 We use tools of molecular biology, biochemistry, cell biology and electrophysiology to test this hypothesis in the following specific aims: Aim 1: Specifically we will: (1.1) identify the residues on the alpha1H II-III loop that mediate high affinity CaMKII binding, (1.2) determine if this binding dynamically localizes the kinase to the channel during cell stimulation, (1.3) introduce peptides or CAMKII调节肾上腺Zona肾小球细胞的抗性通道扰动通道调节并评估ANG II对醛固酮分泌的刺激。 Aim 2: Specifically we will: (2.1) identify the critical residues on GBeta2 subunits that mediate inhibition of alpha1H whole-cell channel activity and alpha1H II-III loop binding, (2.2) establish if Gbeta2 subunits inhibit ohH channels in the excised patch, (2.3) use RNAi and viral-mediated delivery of channel regulation-deficient Gbeta subunits to cells肾上腺Zona肾小球可破坏通道调节并评估多巴胺对醛固酮分泌的抑制作用。