Identification of Critical Phosphorylation Sites on the Carboxy Tail of Melanopsin
Identification of Critical Phosphorylation Sites on the Carboxy Tail of Melanopsin
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DOI：
10.1021/bi401724r
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发表时间：
2014-04-29
期刊：
影响因子：
2.9
通讯作者：
Robinson, Phyllis R.
中科院分区：
文献类型：
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作者：
Blasic, Joseph R., Jr.;Matos-Cruz, Vanessa;Robinson, Phyllis R.
光激活视蛋白经历羧基端磷酸化，这有助于其光响应的失活。黑视素的色素具有一个非常长的羧基尾巴，含有37个丝氨酸和苏氨酸位点，这些位点是G蛋白依赖性激酶（GRK）磷酸化的潜在位点。在这里，我们表明，一个小集群的6至7个网站是足够的光激活小鼠黑视蛋白的失活。令人惊讶的是，这些网站是不同于那些调节视紫红质失活。在斑马鱼中，有五种不同的黑视蛋白基因编码具有不同羧基末端结构域的蛋白质。在同一簇可磷酸化氨基酸中天然发生的变化提供了斑马鱼蛋白失活动力学的多样性。这些结果表明，磷酸化位点的变化提供了黑视素介导的光响应的持续时间和动力学的灵活性。
Light-activated opsins undergo carboxy-terminal phosphorylation, which contributes to the deactivation of their photoresponse. The photopigment melanopsin possesses an unusually long carboxy tail containing 37 serine and threonine sites that are potential sites for phosphorylation by a G-protein dependent kinase (GRK). Here, we show that a small cluster of six to seven sites is sufficient for deactivation of light-activated mouse melanopsin. Surprisingly, these sites are distinct from those that regulate deactivation of rhodopsin. In zebrafish, there are five different melanopsin genes that encode proteins with distinct carboxy-terminal domains. Naturally occurring changes in the same cluster of phosphorylatable amino acids provides diversity in the deactivation kinetics of the zebrafish proteins. These results suggest that variation in phosphorylation sites provides flexibility in the duration and kinetics of melanopsin-mediated light responses.