Expression and subcellular distribution of UNC119a, a protein partner of transducin α subunit in rod photoreceptors.
Expression and subcellular distribution of UNC119a, a protein partner of transducin α subunit in rod photoreceptors.
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UNC119a 的表达和亚细胞分布，UNC119a 是视杆光感受器中转导蛋白 α 亚基的蛋白质伴侣。
DOI：
10.1016/j.cellsig.2012.10.005
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发表时间：
2013
影响因子：
4.8
通讯作者：
Artemyev,NikolaiO
中科院分区：
文献类型：
--
作者：
Sinha,Satyabrata;Majumder,Anurima;Belcastro,Marycharmain;Sokolov,Maxim;Artemyev,NikolaiO
最近发现的视杆细胞转导素α亚基（Gαt1）与UNC119a的相互作用被认为对转导素在光感受器中的运输是重要的。在这项研究中，我们分析了UNC119a在体内不同光照条件下的亚细胞分布。视网膜连续切向切片的免疫荧光和Western印迹分析表明，UNC119a主要存在于视杆内段，一小部分UNC119a也出现浸润视杆外段。这种分布与UNC119a在黑暗中促进转导素从视杆内段运输到外段的作用一致。此外，UNC119a在视杆细胞体和突触区域中的含量较少。UNC119a的亚细胞分布在所有测试的光照条件下基本保持不变，并与Gα t1光依赖性易位后的分布相关。Western印迹定量表明，小鼠视网膜含有约17 pmol的UNC119a，UNC119a与Gαt1的摩尔比约为1：4。因此，光转位Gα t1可以作为UNC119a的主要伙伴。在缺乏Gαt1的小鼠视网膜中，UNC119a的水平下调约2倍，支持了这一作用。Gα t1作为一种主要的蛋白质，可能以光依赖的方式调节其他已知的与感光细胞纤毛运输和突触调节有关的UNC119a相互作用蛋白的功能。
A recently discovered interaction of rod transducin α subunit (Gαt1) with UNC119a is thought to be important for transducin trafficking in photoreceptors. In this study, we analyzed the subcellular distribution of UNC119a under different conditions of illumination in vivo. Analyses by immunofluorescence and Western blotting of retina serial tangential sections demonstrated that UNC119a resides predominantly in the rod inner segment, with a small fraction of UNC119a also appearing to infiltrate the rod outer segment. Such a distribution is consistent with the proposed role of UNC119a in facilitating transducin transport from the rod inner segment to the outer segment in the dark. In addition, UNC119a was present in smaller amounts in the cell body and synaptic region of rods. The profile of UNC119a subcellular distribution remained largely unchanged under all tested conditions of illumination, and correlated with the profile of Gαt1following its light-dependent translocation. Quantification by Western blotting suggested that mouse retina contains ~17pmol of UNC119a, giving a ~1 to 4 molar ratio of UNC119a to Gαt1. Hence, light-translocated Gαt1can serve as a major partner of UNC119a. Supporting this role, the levels of UNC119a were downregulated by about 2-fold in mouse retina lacking Gαt1. As a dominant partner, Gαt1may potentially modulate the function of other known UNC119a-interacting proteins involved in photoreceptor ciliary trafficking and synaptic regulation, in a light-dependent manner.