Institute of Experimental Pediatric Endocrinology, Charité - Universitatsmedizin Berlin, Germany.
Obes Facts. 2009;2(2):80-6. doi: 10.1159/000209862. Epub 2009 Apr 9.
Melanocortin 3 and 4 receptors (MC3R and MC4R) are known to play an essential role in hypothalamic weight regulation. In addition to these two G-protein-coupled receptors (GPCRs), a huge number of other GPCRs are expressed in hypothalamic regions, and some of them are involved in weight regulation. So far, homodimerization was shown for a few of these receptors. Heterodimerization of unrelated receptors may have profound functional consequence but heterodimerization of GPCRs involved in weight regulation was not reported yet.
A selective number of hypothalamically expressed GPCRs were cloned into a eukaryotic expression vector. Cell surface expression was demonstrated by an ELISA approach. Subcellular distribution was investigated by confocal laser microscopy. A sandwich ELISA and fluorescence resonance energy transfer (FRET) were used to determine protein-protein interaction.
Via sandwich ELISA and FRET approach we could demonstrate a robust interaction of the MC4R with GPR7, both of which are expressed in the hypothalamic nucleus paraventricularis. Moreover, we determined a strong interaction of MC3R with the growth hormone secretagogue receptor expressed in the nucleus arcuatus.
Identification GPCR heterodimerization adds to the understanding of the complexity of weight regulation and may provide important information to develop therapeutic strategies to treat obesity.
已知黑皮质素 3 和 4 受体 (MC3R 和 MC4R) 在下丘脑的体重调节中发挥着重要作用。除了这两个 G 蛋白偶联受体 (GPCR) 之外，大量其他 GPCR 在下丘脑区域表达，其中一些与体重调节有关。到目前为止，这些受体中的少数已经显示出同源二聚化。不相关受体的异源二聚化可能会产生深远的功能后果，但涉及体重调节的 GPCR 的异源二聚化尚未报道。
选择一些在下丘脑表达的 GPCR 克隆到真核表达载体中。通过 ELISA 方法证明细胞表面表达。通过共聚焦激光显微镜研究亚细胞分布。夹心 ELISA 和荧光共振能量转移 (FRET) 用于确定蛋白质-蛋白质相互作用。
通过夹心 ELISA 和 FRET 方法，我们可以证明 MC4R 与 GPR7 之间存在强大的相互作用，这两种受体都在下丘脑室旁核表达。此外，我们还确定了 MC3R 与在弓状核表达的生长激素促分泌素受体之间的强烈相互作用。
鉴定 GPCR 异源二聚化增加了对体重调节复杂性的理解，并可能为开发治疗肥胖症的治疗策略提供重要信息。
