Selective Activation of ATF6 and PERK Endoplasmic Reticulum Stress Signaling Pathways Prevent Mutant Rhodopsin Accumulation
Selective Activation of ATF6 and PERK Endoplasmic Reticulum Stress Signaling Pathways Prevent Mutant Rhodopsin Accumulation
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DOI：
10.1167/iovs.12-10222
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发表时间：
2012-10-01
影响因子：
4.4
通讯作者：
Lin, Jonathan H.
中科院分区：
文献类型：
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作者：
Chiang, Wei-Chieh;Hiramatsu, Nobuhiko;Lin, Jonathan H.
目的.许多导致视网膜色素变性的视紫红质突变产生错误折叠的视紫红质蛋白，其保留在内质网（ER）内并导致感光细胞死亡。激活转录因子6（ATF 6）和蛋白激酶RNA样内质网激酶（PERK）控制维持ER稳态的细胞内信号传导途径。本研究的目的是探讨ATF 6和PERK信号通路如何影响细胞内错误折叠的视紫红质，从而寻找新的分子疗法来治疗与ER蛋白错误折叠相关的视网膜疾病。为了检测ATF 6对视紫红质的作用，在表达可诱导的人ATF 6 f（ATF 6的转录激活子结构域）的细胞中表达野生型（WT）或突变型视紫红质。ATF 6 f合成的诱导迅速激活下游基因。为了检查PERK对视紫红质的作用，在表达遗传改变的PERK蛋白Fv 2 E-PERK的细胞中表达WT或突变的视紫红质。添加二聚化分子（AP 20187）可快速激活Fv 2 E-PERK和下游基因。通过使用这些策略，研究了选择性ATF 6或PERK信号传导如何影响WT和突变型视紫红质的命运。ATF 6显著降低细胞中的T17 M、P23 H、Y178 C、C185 R、D190 G、K296 E和S334 ter视紫红质蛋白水平，对单体WT视紫红质蛋白水平的影响最小。相比之下，PERK通路降低了WT、突变型视紫红质和细胞中许多其他蛋白质的水平。这项研究表明，选择性激活ATF 6或PERK可以防止突变型视紫红质在细胞中积累。ATF 6信号传导可特别用于通过优先清除突变型视紫红质和异常视紫红质聚集体来治疗由视紫红质错误折叠引起的视网膜变性疾病。（Invest Ophthalmol维斯科学。2012; 53：7159-7166）DOI：10.1167/iovs.12-10222
PURPOSE. Many rhodopsin mutations that cause retinitis pigmentosa produce misfolded rhodopsin proteins that are retained within the endoplasmic reticulum(ER) and cause photoreceptor cell death. Activating transcription factor 6 (ATF6) and protein kinase RNA-like endoplasmic reticulum kinase (PERK) control intracellular signaling pathways that maintain ER homeostasis. The aim of this study was to investigate how ATF6 and PERK signaling affected misfolded rhodopsin in cells, which could identify new molecular therapies to treat retinal diseases associated with ER protein misfolding.METHODS. To examine the effect of ATF6 on rhodopsin, wildtype (WT) or mutant rhodopsins were expressed in cells expressing inducible human ATF6f, the transcriptional activator domain of ATF6. Induction of ATF6f synthesis rapidly activated downstream genes. To examine PERK's effect on rhodopsin, WT or mutant rhodopsins were expressed in cells expressing a genetically altered PERK protein, Fv2E-PERK. Addition of the dimerizing molecule (AP20187) rapidly activated Fv2E-PERK and downstream genes. By use of these strategies, it was examined how selective ATF6 or PERK signaling affected the fate of WT and mutant rhodopsins.RESULTS. ATF6 significantly reduced T17M, P23H, Y178C, C185R, D190G, K296E, and S334ter rhodopsin protein levels in the cells with minimal effects on monomeric WT rhodopsin protein levels. By contrast, the PERK pathway reduced both levels of WT, mutant rhodopsins, and many other proteins in the cell.CONCLUSIONS. This study indicates that selectively activating ATF6 or PERK prevents mutant rhodopsin from accumulating in cells. ATF6 signaling may be especially useful in treating retinal degenerative diseases arising from rhodopsin misfolding by preferentially clearing mutant rhodopsin and abnormal rhodopsin aggregates. (Invest Ophthalmol Vis Sci. 2012; 53: 7159-7166) DOI: 10.1167/iovs.12-10222