Heterodimerization of the Calcium-sensing receptor with the GabaB receptors in the breast.

乳房中钙敏感受体与 GabaB 受体的异二聚化。

• 批准号: 10674985
• 负责人: John J Wysolmerski
• 金额: $ 38.59万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10674985
• 关键词: 3-Dimensional; Adenylate Cyclase; Affect; Biology; Biosensor; Bone Resorption Stimulation; Breast; Breast Cancer Cell; Breast Epithelial Cells; Calcium; Calcium-Sensing Receptors; Cell secretion; Cells; Cessation of life; Couples; Coupling; Cyclic AMP; Data; Event; Feedback; Fluorescence Resonance Energy Transfer; Functional disorder; G Protein-Coupled Receptor Signaling; G-Protein-Coupled Receptors; GABBR2 gene; GTP-Binding Proteins; Gases; Heterodimerization; In Vitro; Ion Transport; Lactation; MCF10A cells; Mediating; Membrane; Milk; Mus; Nervous System; Neurotransmitters; Organ; Physiology; Production; Proliferating; Protein Secretion; Receptor Signaling; Regulation; Signal Transduction; Skeleton; System; Techniques; Therapeutic; Time; Transfection; bone metabolism; calcium metabolism; cancer cell; cell type; dimer; extracellular; gamma-Aminobutyric Acid; in vivo; malignant breast neoplasm; mammary; mammary epithelium; member; milk production; novel; parathyroid hormone-related protein; protein function; receptor; receptor expression; receptor function; response; three dimensional cell culture; tumor growth; virtual

PROJECT SUMMARY/ABSTRACT The calcium-sensing receptor (CaSR) is a G protein-coupled receptor (GPCR) that signals in response to changes in extracellular calcium. It functions as an obligate dimer and couples to different G-proteins, including Gai or Gas, in a context- or cell type-specific manner. The CaSR is widely expressed and alters proliferation, differentiation, death and ion transport in a variety of cell types, including mammary epithelial cells (MECs), where it regulates the production of parathyroid hormone-related protein (PTHrP) and milk calcium transport. During lactation, activation of the CaSR on MECs inhibits PTHrP secretion by stimulating Gai and reducing cAMP levels. However, in breast cancer cells, activation of the CaSR increases, rather than decreases, PTHrP secretion because, in these cells, the CaSR activates Gas and increases cAMP levels. The CaSR has important functions in both lactation physiology and breast cancer pathophysiology, so it is critical to better understand the regulation of its downstream signaling events in breast epithelial cells. Emerging data demonstrate that the CaSR can heterodimerize with the 2 metabotropic, GabaB receptors, GABBR1 and GABBR2 and the central premise of this application is that heterodimerization of the CaSR with GABBR1 and/or GABBR2 alters CaSR signaling, PTHrP production and transepithelial calcium transport by mammary epithelial cells. Specifically, we hypothesize that, during lactation, reductions in GABBR1 expression and increases in GABBR2 expression promote the formation of CaSR/GABBR2 heterodimers in MECs, which, in turn, increases membrane CaSR expression and reinforces coupling of the CaSR to Gai. In order to explore this hypothesis, we propose 3 Specific Aims. Aim 1 will examine how heterodimerization with GABBR1 or GABBR2 alters CaSR expression, signaling and PTHrP production in breast epithelial cells in vitro. Aim 2 will use genetically modified mice to examine whether heterodimerization with GABBR2 regulates CaSR expression and function in the lactating breast in vivo. Aim 3 will use genetically modified mice to examine whether heterodimerization with GABBR1 regulates CaSR expression and function in the lactating breast in vivo. The studies outlined in this proposal will explore novel biology of great importance for lactation physiology that also has implications for breast cancer pathophysiology. These studies have the potential to discover novel ways to target the CaSR therapeutically.

项目概要/摘要 钙敏感受体 (CaSR) 是一种 G 蛋白偶联受体 (GPCR)，可发出响应信号 细胞外钙的变化。它作为专性二聚体发挥作用并与不同的 G 蛋白偶联， 包括 Gai 或 Gas，以上下文或细胞类型特定的方式。 CaSR 广泛表达并改变 多种细胞类型（包括乳腺上皮细胞）的增殖、分化、死亡和离子转运 （MEC），调节甲状旁腺激素相关蛋白（PTHrP）和乳钙的产生 运输。哺乳期间，MEC 上 CaSR 的激活通过刺激 Gai 和 PTHrP 抑制 PTHrP 分泌。 降低 cAMP 水平。然而，在乳腺癌细胞中，CaSR 的激活增加，而不是增加。 PTHrP 分泌减少，因为在这些细胞中，CaSR 激活 Gas 并增加 cAMP 水平。这 CaSR 在哺乳生理学和乳腺癌病理生理学中都具有重要功能，因此至关重要 更好地了解乳腺上皮细胞中下游信号事件的调节。新兴数据 证明 CaSR 可以与 2 个代谢型 GabaB 受体、GABBR1 和 GABBR2 和该应用的中心前提是 CaSR 的异二聚化 GABBR1 和/或 GABBR2 改变 CaSR 信号传导、PTHrP 产生和跨上皮钙 由乳腺上皮细胞运输。具体来说，我们假设，在哺乳期间， GABBR1表达和GABBR2表达增加促进CaSR/GABBR2的形成 MEC 中的异二聚体，进而增加膜 CaSR 表达并增强 CaSR 至 Gai。为了探索这一假设，我们提出了 3 个具体目标。目标 1 将研究如何 与 GABBR1 或 GABBR2 的异二聚化改变 CaSR 表达、信号传导和 PTHrP 产生 体外乳腺上皮细胞。目标2将使用基因改造小鼠来检查异二聚化是否发生 与 GABBR2 一起调节体内哺乳期乳腺中 CaSR 的表达和功能。目标 3 将使用 转基因小鼠检查 GABBR1 异二聚化是否调节 CaSR 表达 并在体内哺乳期乳腺中发挥作用。本提案中概述的研究将探索新的生物学 对哺乳生理学非常重要，对乳腺癌病理生理学也有影响。这些 研究有可能发现靶向 CaSR 治疗的新方法。