A rhodopsin mutant linked to autosomal dominant retinitis pigmentosa is prone to aggregate and interacts with the ubiquitin proteasome system
A rhodopsin mutant linked to autosomal dominant retinitis pigmentosa is prone to aggregate and interacts with the ubiquitin proteasome system
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DOI：
10.1074/jbc.m204955200
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发表时间：
2002-09-13
影响因子：
4.8
通讯作者：
Kopito, RR
中科院分区：
文献类型：
--
作者：
Illing, ME;Rajan, RS;Kopito, RR
遗传性视网膜变性以色素性视网膜炎 (RP) 为代表，这是一组异质性遗传性疾病，会导致感光细胞、视网膜色素上皮和脉络膜遭到破坏。这类致盲病症影响着全世界超过 150 万人。大约 30-40% 的人类常染色体显性 (AD) RP 是由视紫红质基因中显性遗传的错义突变引起的。在这里，我们发现 P23H（美国患者中最常见的 RP 突变）使视紫红质极易在转染细胞的细胞质中形成高分子量寡聚体。聚集的 P23H 在聚集体中积累，聚集体是中心粒周围的包涵体，需要完整的微管细胞骨架才能形成。使用荧光共振能量转移 (FRET)，我们观察到 P23H 即使在极低的表达水平下也会在细胞质中聚集。我们的数据表明，P23H 突变使蛋白质不稳定，并使其被泛素蛋白酶体系统降解。 P23H 通过蛋白酶体抑制剂和泛素显性失活形式的共表达来稳定。我们发现，P23H（而非野生型视紫红质）的表达会导致泛素蛋白酶体系统普遍受损，这表明光感受器变性的机制将 RP 与广泛的神经退行性疾病联系起来。
The inherited retinal degenerations are typified by retinitis pigmentosa (RP), a heterogeneous group of inherited disorders that causes the destruction of photoreceptor cells, the retinal pigmented epithelium, and choroid. This group of blinding conditions affects over 1.5 million persons worldwide. Approximately 30-40% of human autosomal dominant (AD) RP is caused by dominantly inherited missense mutations in the rhodopsin gene. Here we show that P23H, the most frequent RP mutation in American patients, renders rhodopsin extremely prone to form high molecular weight oligomeric species in the cytoplasm of transfected cells. Aggregated P23H accumulates in aggresomes, which are pericentriolar inclusion bodies that require an intact microtubule cytoskeleton to form. Using fluorescence resonance energy transfer (FRET), we observe that P23H aggregates in the cytoplasm even at extremely low expression levels. Our data show that the P23H mutation destabilizes the protein and targets it for degradation by the ubiquitin proteasome system. P23H is stabilized by proteasome inhibitors and by co-expression of a dominant negative form of ubiquitin. We show that expression of P23H, but not wild-type rhodopsin, results in a generalized impairment of the ubiquitin proteasome system, suggesting a mechanism for photoreceptor degeneration that links RP to a broad class of neurodegenerative diseases.