Busnelli Marta, Kleinau Gunnar, Muttenthaler Markus, Stoev Stoytcho, Manning Maurice, Bibic Lucka, Howell Lesley A, McCormick Peter J, Di Lascio Simona, Braida Daniela, Sala Mariaelvina, Rovati G Enrico, Bellini Tommaso, Chini Bice
CNR, Institute of Neuroscience , Milan, Italy 20129.
Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano , Milan, Italy 20129.
J Med Chem. 2016 Aug 11;59(15):7152-66. doi: 10.1021/acs.jmedchem.6b00564. Epub 2016 Jul 28.
Dimeric/oligomeric states of G-protein coupled receptors have been difficult to target. We report here bivalent ligands consisting of two identical oxytocin-mimetics that induce a three order magnitude boost in G-protein signaling of oxytocin receptors (OTRs) in vitro and a 100- and 40-fold gain in potency in vivo in the social behavior of mice and zebrafish. Through receptor mutagenesis and interference experiments with synthetic peptides mimicking transmembrane helices (TMH), we show that such superpotent behavior follows from the binding of the bivalent ligands to dimeric receptors based on a TMH1-TMH2 interface. Moreover, in this arrangement, only the analogues with a well-defined spacer length (∼25 Å) precisely fit inside a channel-like passage between the two protomers of the dimer. The newly discovered oxytocin bivalent ligands represent a powerful tool for targeting dimeric OTR in neurodevelopmental and psychiatric disorders and, in general, provide a framework to untangle specific arrangements of G-protein coupled receptor dimers.
G蛋白偶联受体的二聚体/寡聚体状态一直难以靶向作用。我们在此报告由两个相同的催产素模拟物组成的二价配体，其在体外可使催产素受体（OTRs）的G蛋白信号传导增强三个数量级，在体内对小鼠和斑马鱼的社交行为而言，效力提高了100倍和40倍。通过受体诱变以及与模拟跨膜螺旋（TMH）的合成肽进行干扰实验，我们表明这种超强效力行为源于二价配体基于TMH1-TMH2界面与二聚体受体的结合。此外，在这种排列中，只有具有明确间隔长度（约25 Å）的类似物能够精确地契合二聚体两个原体之间的通道样通道内部。新发现的催产素二价配体是用于靶向神经发育和精神疾病中二聚体OTR的有力工具，总体而言，为理清G蛋白偶联受体二聚体的特定排列提供了一个框架。
