Cleavage of the retinal pigment epithelium-specific protein RPE65 under oxidative stress

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• 作者：Hyunju Lee ; Hyewon Chung ; Hilal Arnouk ; Folami Lamoke ; Richard C. Hunt ; William J.M. Hrushesky ; Patricia A. Wood ; Sung Haeng Lee ; Wan Jin Jahng
• 关键词：Visual cycle ; RPE65 ; Retinal pigment epithelium ; Oxidative stress ; Light
• 刊名：International Journal of Biological Macromolecules
• 出版年：2010
• 出版时间：1 August 2010
• 年：2010
• 卷：47
• 期：2
• 页码：104-108
• 全文大小：254 K

文摘

The regeneration of the 11-cis-retinyl imine chromophore of rhodopsin during the visual cycle and mechanisms that control this process are central questions in the field of vision research. The retinal pigment epithelium (RPE)-specific protein RPE65 is centrally involved in the isomerization and hydrolysis of all-trans-retinyl esters. In this study, we investigated RPE65 cleavage and potential regulatory mechanisms under oxidative stress conditions. The D407 RPE cell cultures were exposed to H₂O₂ (100–1000 μM). Changes in the levels of RPE65 and proteins related to apoptosis were investigated using gel electrophoresis and western blotting. Mass spectrometry was used to confirm the identity of RPE65. C57BL/6J (M450) and C3HeB/FeJ (L450) mice were used for in vivo experiments. We found that a novel 45 kDa truncated fragment of the RPE65 protein, designated RPE45, appears in RPE cells upon light exposure or oxidative stress. RPE45 is generated in vitro by recombinant caspases via an ubiquitination-dependent mechanism. Collectively, our results indicate that oxidative stress during the visual cycle results in cleavage of RPE65.