Department of Cell Biology, University of Oklahoma Health Sciences Center, BMSB 781, 940 Stanton L. Young Blvd., Oklahoma City, OK 73104, USA.
Exp Eye Res. 2009 Oct;89(4):559-67. doi: 10.1016/j.exer.2009.05.010. Epub 2009 Jun 11.
Tyrosine-O-sulfation, a post-translational modification, is catalyzed by two independent tyrosylprotein sulfotransferases (TPSTs). As an initial step towards understanding the role of TPSTs in retinal function, this study was undertaken to determine the extent to which tyrosine-O-sulfation of proteins is utilized in the retina. A previously characterized anti-sulfotyrosine antibody was used to determine the presence and localization of tyrosine-O-sulfated proteins (TOSPs) in the retina. Using Western blot, RT-PCR and immunohistochemical analyses, we detected TOSPs in the retinas from diverse species, including frog, fish, mouse and human. Some of the variability in the observed sizes of retinal TOSPs in the mouse, at least, may result from differential patterns of glycosylation; however, there seem to be species-specific sulfated retinal proteins as well. TOSPs were detected in most of the retinal layers as well as in the retinal pigment epithelium from human and mouse. Several retinal TOSPs were detected in the inter-photoreceptor matrix, which is consistent with the secreted nature of some sulfated proteins. Transcripts for both TPST-1 and TPST-2 were expressed in both the human and mouse retinas. These data show that retinal protein tyrosine-O-sulfation is highly conserved which suggest a functional significance of these proteins to retinal function and structure.
酪氨酸-O-硫酸化是一种翻译后修饰，由两种独立的酪氨酸蛋白硫酸转移酶（TPSTs）催化。为了初步了解 TPSTs 在视网膜功能中的作用，本研究旨在确定蛋白质酪氨酸-O-硫酸化在视网膜中的利用程度。本研究使用先前鉴定的抗硫酸酪氨酸抗体来确定视网膜中酪氨酸-O-硫酸化蛋白（TOSPs）的存在和定位。通过 Western blot、RT-PCR 和免疫组织化学分析，我们在来自不同物种的视网膜中检测到了 TOSPs，包括青蛙、鱼类、小鼠和人类。在小鼠中，观察到的视网膜 TOSPs 的大小存在一些差异，至少可能是由于糖基化模式的不同；然而，似乎也存在特定于物种的硫酸化视网膜蛋白。TOSPs 不仅在人类和小鼠的视网膜各层中被检测到，也在视网膜色素上皮中被检测到。一些视网膜 TOSPs 在光感受器间基质中被检测到，这与一些硫酸化蛋白的分泌性质一致。TPST-1 和 TPST-2 的转录本在人和鼠的视网膜中均有表达。这些数据表明视网膜蛋白酪氨酸-O-硫酸化高度保守，这表明这些蛋白对视网膜功能和结构具有重要的功能意义。
