Gq activity- and β-arrestin-1 scaffolding-mediated ADGRG2/CFTR coupling are required for male fertility.

Luminal fluid reabsorption plays a fundamental role in male fertility. We demonstrated that the ubiquitous GPCR signaling proteins Gq and β-arrestin-1 are essential for fluid reabsorption because they mediate coupling between an orphan receptor ADGRG2 (GPR64) and the ion channel CFTR. A reduction in protein level or deficiency of ADGRG2, Gq or β-arrestin-1 in a mouse model led to an imbalance in pH homeostasis in the efferent ductules due to decreased constitutive CFTR currents. Efferent ductule dysfunction was rescued by the specific activation of another GPCR, AGTR2. Further mechanistic analysis revealed that β-arrestin-1 acts as a scaffold for ADGRG2/CFTR complex formation in apical membranes, whereas specific residues of ADGRG2 confer coupling specificity for different G protein subtypes, this specificity is critical for male fertility. Therefore, manipulation of the signaling components of the ADGRG2-Gq/β-arrestin-1/CFTR complex by small molecules may be an effective therapeutic strategy for male infertility.

管腔液重吸收在男性生育能力中起着至关重要的作用。我们证明了普遍存在的G蛋白偶联受体（GPCR）信号蛋白Gq和β - 抑制蛋白 - 1对液体重吸收至关重要，因为它们介导孤儿受体ADGRG2（GPR64）和离子通道囊性纤维化跨膜传导调节因子（CFTR）之间的偶联。在小鼠模型中，ADGRG2、Gq或β - 抑制蛋白 - 1的蛋白水平降低或缺失会导致由于组成型CFTR电流减少而使输出小管的pH稳态失衡。通过特异性激活另一种GPCR（血管紧张素Ⅱ受体2，AGTR2）可挽救输出小管功能障碍。进一步的机制分析表明，β - 抑制蛋白 - 1作为顶膜中ADGRG2/CFTR复合物形成的支架，而ADGRG2的特定残基赋予不同G蛋白亚型偶联特异性，这种特异性对男性生育能力至关重要。因此，通过小分子调控ADGRG2 - Gq/β - 抑制蛋白 - 1/CFTR复合物的信号成分可能是治疗男性不育的一种有效治疗策略。