Division of Biochemistry, Department of Neuroscience, Carl von Ossietzky Universität Oldenburg, 26111, Oldenburg, Germany.
Neurosensorics/Animal Navigation, Institute of Biology and Environmental Sciences, Carl von Ossietzky Universität Oldenburg, 26111, Oldenburg, Germany.
Sci Rep. 2024 Nov 16;14(1):28326. doi: 10.1038/s41598-024-79699-z.
Vision and magnetoreception in navigating songbirds are strongly connected as recent findings link a light dependent radical-pair mechanism in cryptochrome proteins to signalling pathways in cone photoreceptor cells. A previous yeast-two-hybrid screening approach identified six putative candidate proteins showing binding to cryptochrome type 4a. So far, only the interaction of the cone specific G-protein transducin α-subunit was investigated in more detail. In the present study, we compare the binding features of the G-protein α-subunit with those of another candidate from the yeast-two-hybrid screen, cellular retinol binding protein. Purified recombinant European robin retinol binding protein bound retinol with high affinity, displaying an EC of less than 5 nM, thereby demonstrating its functional state. We applied surface plasmon resonance and a Förster resonance transfer analysis to test for interactions between retinol binding protein and cryptochrome 4a. In the absence of retinol, we observed no robust binding events, which contrasts the strong interaction we observed between cryptochrome 4a and the G-protein α-subunit. We conclude that retinol binding protein is unlikely to be involved in the primary magnetosensory signalling cascade.
在导航鸣禽的视觉和磁受体中，最近的发现将隐花色素蛋白中的光依赖性自由基对机制与视锥光感受器细胞中的信号通路联系起来，这两者紧密相连。先前的酵母双杂交筛选方法确定了六个假定的候选蛋白，这些蛋白显示与隐花色素 4a 结合。到目前为止，只有视锥特异性 G 蛋白转导素 α 亚基的相互作用得到了更详细的研究。在本研究中，我们将 G 蛋白 α 亚基的结合特征与酵母双杂交筛选中的另一个候选蛋白——细胞视黄醇结合蛋白进行了比较。纯化的重组欧洲知更鸟视黄醇结合蛋白与视黄醇具有高亲和力结合，EC 值小于 5 nM，从而证明了其功能状态。我们应用表面等离子体共振和Förster 共振能量转移分析来测试视黄醇结合蛋白与隐花色素 4a 之间的相互作用。在没有视黄醇的情况下，我们没有观察到稳定的结合事件，这与我们观察到的隐花色素 4a 与 G 蛋白 α 亚基之间的强烈相互作用形成对比。我们得出结论，视黄醇结合蛋白不太可能参与初级磁感觉信号级联。
