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Signaling Mechanisms of the Angll Receptor AT2

Angll 受体 AT2 的信号传导机制

基本信息

批准号：
7228718
负责人：
Lakshmidevi Pulakat
金额：
$ 5.64万
依托单位：
MISSISSIPPI STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1998
资助国家：
美国
起止时间：
1998-09-04 至 2007-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7228718
关键词：
CHO cells Xenopus oocyte angiotensin II biological signal transduction cell growth regulation cyclic GMP hormone receptor immunoprecipitation insulin receptor ligands phosphorylation protein protein interaction protein structure function protooncogene receptor expression

项目摘要

DESCRIPTION (provided by applicant): Angiotensin II (Ang II) is well known for its involvement in the regulation of blood pressure and hydromineral balance, as well as in the pathogenesis of hypertension, congestive heart failure and a number of other clinical conditions. We have demonstrated that co-expression of the Angll receptors AT1 and AT2 in Xenopus oocytes resulted in AT2-mediated inhibition of the AT1-mediated IP3 production, and that the region of the 3rd ICL of AT2 that spans amino acids 240-256 is sufficient for this function. We have also shown that AT2 directly interacts with the ErbB3 receptor and has proposed that this could be one of the mechanisms by which AT2 exerts its anti-growth effects. The general goal of this research proposal is to characterize the signaling mechanisms of the Ang II receptor AT2, and elucidate the role of direct protein-protein interaction in this function. With the help of funding from AREA grant R15HL60241-01, we generated a large number of the AT2 mutants and have demonstrated two new AT2-mediated signaling mechanisms in Xenopus oocytes:a) the AT2-mediated inhibition of the ATl-mediated IP3 production, and b) AT2-mediated cGMP reduction.We have also shown that AT2 directly interacts with the ErbB3 receptor and have proposed that this could be a mechanism by which AT2 exerts its anti-growth effects. The specific aim 1 of this proposal is to identify the region of the AT2 involved in reduction of basal levels of cGMP in Xenopus oocytes, and determine whether the AT2 exerts a negative regulatory effect on the AT1 mediated increase of the cGMP in these cells. The specific aim 2 is to identify the region of the AT2 responsible for the inhibition of tyrosine phosphorylation of the insulin receptor (IR) beta chain in Chinese Hamster Ovary (CHO) cells, and determine whether this AT2-mediated inhibition of IR phosphorylation is via direct protein-protein interaction. We propose that a direct interaction between the AT2 and IR beta chain, similar to what we have seen in the case of AT2 and ErbB3 interaction, may be involved in AT2-mediated inhibition of IR signaling. We will use the AT2 mutants to determine which region of AT2 is involved in the inhibition of IR signaling in CHO cells. Thus, funding of this proposal will not only help in elucidating newly identified signaling mechanisms of Ang II, but also allow us to continue the training we have been giving to a large number of graduate and undergraduate students in cellular and molecular research at BGSU.

描述（由申请人提供）：血管紧张素II （Ang II）因其参与血压和水矿物质平衡的调节，以及高血压，充血性心力衰竭和许多其他临床疾病的发病机制而闻名。我们已经证明，在非洲爪蟾卵母细胞中，Angll受体AT1和AT2的共表达导致AT2介导的IP3产生的抑制，并且AT2的第3 ICL横跨240-256个氨基酸的区域足以实现这一功能。我们还发现AT2直接与ErbB3受体相互作用，并提出这可能是AT2发挥其抗生长作用的机制之一。本研究计划的总体目标是表征Ang II受体AT2的信号传导机制，并阐明蛋白质-蛋白质直接相互作用在该功能中的作用。在AREA基金R15HL60241-01的帮助下，我们产生了大量的AT2突变体，并在爪蟾卵细胞中证明了两种新的AT2介导的信号机制：a) AT2介导的AT2介导的IP3产生的抑制，b) AT2介导的cGMP减少。我们还发现AT2直接与ErbB3受体相互作用，并提出这可能是AT2发挥其抗生长作用的机制。本提案的具体目的1是确定AT2参与爪蟾卵母细胞cGMP基础水平降低的区域，并确定AT2是否对AT1介导的爪蟾卵母细胞cGMP升高发挥负调控作用。具体目的2是确定AT2负责抑制中国仓鼠卵巢（CHO）细胞中胰岛素受体(IR) β链酪氨酸磷酸化的区域，并确定这种AT2介导的对IR磷酸化的抑制是否通过直接的蛋白-蛋白相互作用。我们提出AT2和IR β链之间的直接相互作用，类似于我们在AT2和ErbB3相互作用的情况下所看到的，可能参与了AT2介导的IR信号传导抑制。我们将使用AT2突变体来确定AT2的哪个区域参与了CHO细胞中IR信号的抑制。因此，这项提案的资助不仅有助于阐明新发现的Ang II的信号机制，而且还使我们能够继续在BGSU对大量研究生和本科生进行细胞和分子研究的培训。