Identification of Key Residues Determining Isomerohydrolase Activity of Human RPE65

Takahashi, Yusuke; Moiseyev, Gennadiy; Xing, Jian

doi:10.1074/jbc.m114.558619

Cited by 8 publications

(5 citation statements)

References 42 publications

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“…It is responsible for transporting nutrients and metabolites between the choroidal blood supply and the neural retina, and is part of the visual cycle, converting all- trans -retinol into 11- cis -retinal. The 11-cis-retinal is transported into the retina and utilized by G-protein coupled receptor, opsin, as the chromophore for phototransduction (17, 18). Furthermore, photoreceptor outer segments (POS) that are shed daily are removed by the RPE through receptor-mediated phagocytosis (17, 19).…”

Section: Introductionmentioning

confidence: 99%

Phagocytosed photoreceptor outer segments activate mTORC1 in the retinal pigment epithelium

Egbejimi

Dharmat

et al. 2018

Sci. Signal.

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The retinal pigment epithelium (RPE) transports nutrients and metabolites between the microvascular bed that maintains the outer retina and photoreceptor neurons. The RPE removes photoreceptor outer segments (POS) by receptor-mediated phagocytosis, a process that peaks in the morning. Uptake and degradation of POS initiates signaling cascades in the RPE. Upstream stimuli from various metabolic activities converge on mechanistic target of rapamycin complex 1 (mTORC1), and aberrant mTORC1 signaling is implicated in aging and age-related degeneration of the RPE. In the current study, we measured mTORC1-mediated responses to RPE phagocytosis in vivo and in vitro. During the morning burst of POS shedding, there was transient activation of mTORC1-mediated signaling in the RPE. POS activated mTORC1 through lysosome-independent mechanisms and engulfed POS served as a docking platform for mTORC1 assembly. The identification of POS as endogenous stimuli of mTORC1 in the RPE provides a mechanistic link underlying the photoreceptor-RPE interaction in the outer retina.

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Section: Introductionmentioning

confidence: 99%

Phagocytosed photoreceptor outer segments activate mTORC1 in the retinal pigment epithelium

Egbejimi

Dharmat

et al. 2018

Sci. Signal.

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“…In fact, the effect of such mutation on h RPE65 hydrolase activity was experimentally evaluated and showed to be non-deleterious. In particular, the mutated residue I302 corresponds to the homolog residue of chicken RPE65, known to be endowed with a higher hydrolase activity with respect to the human isoform; consistently, N302I mutation demonstrated to slightly improve the catalytic activity of the human enzyme (about 125% of activity compared to wild type) 29 .…”

Section: Resultsmentioning

confidence: 95%

Predicting potentially pathogenic effects of hRPE65 missense mutations: a computational strategy based on molecular dynamics simulations

Poli

Barravecchia

Demontis

et al. 2022

Journal of Enzyme Inhibition and Medicinal Chemistry

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The human retinal pigment epithelium-specific 65-kDa protein ( h RPE65) plays a crucial role within the retinoid visual cycle and several mutations affecting either its expression level or its enzymatic function are associated with inherited retinal diseases such as Retinitis Pigmentosa. The gene therapy product voretigene neparvovec (Luxturna) has been recently approved for treating hereditary retinal dystrophies; however, the treatment is currently accessible only to patients presenting confirmed biallelic mutations that severely impair h RPE65 function, and many reported h RPE65 missense mutations lack sufficient evidences for proving their pathogenicity. In this context, we developed a computational approach aimed at evaluating the potential pathogenic effect of h RPE65 missense variants located on the dimerisation domain of the protein. The protocol evaluates how mutations may affect folding and conformation stability of this protein region, potentially helping clinicians to evaluate the eligibility for gene therapy of patients diagnosed with this type of h RPE65 variant of uncertain significance.

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“…The homozygous substitution c.1451G>A resulting in p.Gly484Asp was previously reported in two male patients with a severe form of LCA [ 28 ]. The amino acid glycine at the residue 484 is highly conserved between species [ 29 ], and this missense variant p.Gly484Val is predicted by the in silico analyses to affect protein function, although functional analyses are required to elucidate the pathogenicity of this substitution. Visual acuity varies between patients with different RPE65 genotypes, but also between the members of the same family examined in this study (from 1/50 to light perception and projection in Family 6).…”

Section: Discussionmentioning

confidence: 99%

Novel gene variants in Polish patients with Leber congenital amaurosis (LCA)

Skorczyk-Werner

Niedziela

Stopa

et al. 2020

Orphanet J Rare Dis

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Background Leber congenital amaurosis (LCA) is a rare retinal disease that is the most frequent cause of congenital blindness in children and the most severe form of inherited retinal dystrophies. To date, 25 genes have been implicated in the pathogenesis of LCA. As gene therapy is becoming available, the identification of potential treatment candidates is crucial. The aim of the study was to report the molecular basis of Leber congenital amaurosis in 22 Polish families. Methods Single Nucleotide Polymorphism-microarray for LCA genes or Next Generation Sequencing diagnostic panel for LCA genes (or both tests) were performed to identify potentially pathogenic variants. Bidirectional Sanger sequencing was carried out for validation and segregation analysis of the variants identified within the families. Results The molecular background was established in 22 families. From a total of 24 identified variants, 23 were predicted to affect protein-coding or splicing, including 10 novel variants. The variants were identified in 7 genes: CEP290, GUCY2D, RPE65, NMNAT1, CRB1, RPGRIP1, and CRX. More than one-third of the patients, with clinical LCA diagnosis confirmed by the results of molecular analysis, appeared to be affected with a severe form of the disease: LCA10 caused by the CEP290 gene variants. Intronic mutation c.2991+1655A>G in the CEP290 gene was the most frequent variant identified in the studied group. Conclusions This study provides the first molecular genetic characteristics of patients with Leber congenital amaurosis from the previously unexplored Polish population. Our study expands the mutational spectrum as we report 10 novel variants identified in LCA genes. The fact that the most frequent causes of the disease in the studied group of Polish patients are mutations in one out of three genes that are currently the targets for gene therapy (CEP290, GUCY2D, and RPE65) strongly emphasizes the importance of the molecular background analyses of LCA in Polish patients.

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Identification of Key Residues Determining Isomerohydrolase Activity of Human RPE65

Cited by 8 publications

References 42 publications

Phagocytosed photoreceptor outer segments activate mTORC1 in the retinal pigment epithelium

Phagocytosed photoreceptor outer segments activate mTORC1 in the retinal pigment epithelium

Predicting potentially pathogenic effects of hRPE65 missense mutations: a computational strategy based on molecular dynamics simulations

Novel gene variants in Polish patients with Leber congenital amaurosis (LCA)

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