Department of Biological Science, Graduate School of Science and Engineering, Iwate University, Morioka, Japan.
Department of Biochemistry and Molecular Biology, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Japan.
Biochem Biophys Res Commun. 2020 Apr 9;524(3):542-548. doi: 10.1016/j.bbrc.2020.01.127. Epub 2020 Jan 31.
ES1 homologs are conserved among prokaryotes and eukaryotes, and the gene expression of ES1 homologs has been confirmed in diverse mammalian tissues. However, the localization and function of mammalian ES1 proteins remain poorly understood. ES1 protein was found specifically expressed in the cone cells of zebrafish and was proposed to contribute to the formation of mega mitochondria. We also observed mega mitochondria in the cone cells of porcine retinas, which raised the question regarding the localization of the porcine ES1. Therefore, in the present study, we aimed to determine the localization of ES1 in porcine retinas. We prepared a rabbit polyclonal antibody against the ES1 C-terminal and performed western blotting analysis and immunoelectron microscopy. The ES1 was found to be localized mainly in the mitochondrial intermembrane space of the porcine retinal cells. Immunopositive signals for ES1 were observed in the mitochondria of almost all retinal cells, and not specifically in cone cells. Our results and the ES1 sequences indicated that the glyoxalase III activity of ES1 might contribute to the stable functionality of the active mitochondria in a protective manner.
ES1 同源物在原核生物和真核生物中是保守的，并且已经在多种哺乳动物组织中证实了 ES1 同源物的基因表达。然而，哺乳动物 ES1 蛋白的定位和功能仍知之甚少。ES1 蛋白被发现特异性表达在斑马鱼的视锥细胞中，并被提出有助于形成巨型线粒体。我们还观察到猪视网膜的视锥细胞中存在巨型线粒体，这就提出了关于猪 ES1 定位的问题。因此，在本研究中，我们旨在确定 ES1 在猪视网膜中的定位。我们制备了针对 ES1 C 末端的兔多克隆抗体，并进行了 Western blot 分析和免疫电镜分析。结果发现 ES1 主要定位于猪视网膜细胞的线粒体膜间隙中。在几乎所有视网膜细胞的线粒体中都观察到 ES1 的免疫阳性信号，而不是特异性地在视锥细胞中。我们的结果和 ES1 序列表明，ES1 的甘油醛 3-磷酸脱氢酶活性可能以保护的方式有助于稳定活性线粒体的功能。
