CTRP5 is a membrane-associated and secretory protein in the RPE and ciliary body and the S163R mutation of CTRP5 impairs its secretion
CTRP5 is a membrane-associated and secretory protein in the RPE and ciliary body and the S163R mutation of CTRP5 impairs its secretion
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DOI：
10.1167/iovs.06-0312
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发表时间：
2006-12-01
影响因子：
4.4
通讯作者：
Ayyagari, Radha
中科院分区：
文献类型：
--
作者：
Mandal, Md Nawajes A.;Vasireddy, Vidyullatha;Ayyagari, Radha
目的。在之前的一项研究中，据报道，补体 1q 肿瘤坏死因子相关蛋白 5 (CTRP5/C1QTNF5) 中的 S163R 突变与早发性长前小带 (LAZ) 和迟发性视网膜变性 (L-ORD) 相关。参与表型的眼组织是后段的视网膜色素上皮（RPE）和前段的睫状体上皮（CE）和晶状体。本研究的目的是表征小鼠Ctrp5基因的空间和时间表达，确定组织和亚细胞定位，并研究S163R突变的影响。方法。通过定量 (q) RT-PCR 和原位杂交研究了小鼠中 Ctrp5 基因的表达。通过蛋白质印迹分析、免疫组织化学和免疫电子显微镜研究 CTRP5 蛋白的表达和分布。通过免疫荧光和免疫印迹分析确定MDCK和COS-7细胞中野生型和突变型CTRP5的细胞定位。结果。在成年小鼠的睫状体 (CB) 和 RPE 中检测到显着水平的 Ctrp5 表达，并且表达在胚胎发生的非常早期阶段就开始了。免疫组织化学分析显示 CTRP5 蛋白存在于 RPE 的顶突中，并形成与 RPE 侧膜相关的六边形网格。在睫状体中，CTRP5 定位于 CE 的顶端，即双层睫状上皮细胞之间的区域。通过免疫电子显微镜进一步证实了 RPE 和 CE 中 CTRP5 的膜关联。此外，使用培养细胞表明CTRP5是一种分泌蛋白，并且其分泌因S163R突变而受损。结论。 CTRP5 是一种分泌性膜相关蛋白，定位于 RPE 和 CB 的侧膜和顶膜。突变蛋白的分泌受损可能是 L-ORD 和 LAZ 病理生理学的基础。
PURPOSE. In a prior study, a S163R mutation in the complement-1q tumor necrosis factor-related protein 5 (CTRP5/C1QTNF5) was reported to be associated with early-onset long anterior zonules (LAZ) and late-onset retinal degeneration (L-ORD). The ocular tissues involved in the phenotype are the retinal pigment epithelium (RPE) in the posterior segment and ciliary epithelium (CE) and lens in the anterior segment. The purpose of this study was to characterize the spatial and temporal expression of the mouse Ctrp5 gene, determine tissue and subcellular localization, and study the effect of the S163R mutation.METHODS. The expression of the Ctrp5 gene in the mouse was studied by quantitative (q) RT-PCR and in situ hybridization. CTRP5 protein expression and distribution were studied by Western blot analysis, immunohistochemistry, and immunoelectron microscopy. Cellular location of wild-type and mutant CTRP5 in MDCK and COS-7 cells was determined by immunofluorescence and immunoblot analysis.RESULTS. A significant level of Ctrp5 expression was detected in the adult mouse in the ciliary body (CB) and RPE, and expression started at a very early stage of embryogenesis. Immunohistochemical analysis showed CTRP5 protein in the apical processes of the RPE and forming a hexagonal lattice associated with the RPE lateral membranes. In the ciliary body, CTRP5 was localized to the apical aspects of the CE, the region between the bilayered ciliary epithelial cells. The membrane association of CTRP5 in the RPE and CE was further confirmed by immunoelectron microscopy. Furthermore, cultured cells were used to show that the CTRP5 is a secretory protein and that its secretion is impaired by the S163R mutation.CONCLUSIONS. CTRP5, a secretory and membrane-associated protein, is localized to the lateral and apical membranes of the RPE and CB. Impaired secretion of the mutant protein may underlie the pathophysiology of L-ORD and LAZ.