Disease-Causing Mutations in BEST1 Gene Are Associated with Altered Sorting of Bestrophin-1 Protein

Doumanov, Jordan; Zeitz, Christina; Gimenez, Paloma Dominguez; Audo, Isabelle; Krishna, Amresh; Alfano, Giovanna; Diaz, Maria Diaz Bellido; Moskova-Doumanova, Veselina; Lancelot, Marie-Elise; Sahel, José‐Alain; Nandrot, Emeline F.; Bhattacharya, Siladitya

doi:10.3390/ijms140715121

Cited by 13 publications

(11 citation statements)

References 52 publications

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“…MDCK II cells adopt a polarised morphology typical of epithelial cells that we and others have shown can recapitulate the authentic localisation of WT bestrophin-1 (Mostov et al, 2003; Davidson et al, 2009; Milenkovic et al, 2011; Doumanov et al, 2013; Johnson et al, 2013). MDCKII stable cells lines were grown on Transwell porous filters for 5-6 days until they formed a confluent monolayer, then bestrophin-1 expression was induced by addition of tetracycline.…”

Section: Resultssupporting

confidence: 62%

Restoration of mutant bestrophin-1 expression, localisation and function in a polarised epithelial cell model

Uggenti

Briant

Streit

et al. 2016

Disease Models &Amp; Mechanisms

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Autosomal recessive bestrophinopathy (ARB) is a retinopathy caused by mutations in the bestrophin-1 protein, which is thought to function as a Ca2+-gated Cl− channel in the basolateral surface of the retinal pigment epithelium (RPE). Using a stably transfected polarised epithelial cell model, we show that four ARB mutant bestrophin-1 proteins were mislocalised and subjected to proteasomal degradation. In contrast to the wild-type bestrophin-1, each of the four mutant proteins also failed to conduct Cl− ions in transiently transfected cells as determined by whole-cell patch clamp. We demonstrate that a combination of two clinically approved drugs, bortezomib and 4-phenylbutyrate (4PBA), successfully restored the expression and localisation of all four ARB mutant bestrophin-1 proteins. Importantly, the Cl− conductance function of each of the mutant bestrophin-1 proteins was fully restored to that of wild-type bestrophin-1 by treatment of cells with 4PBA alone. The functional rescue achieved with 4PBA is significant because it suggests that this drug, which is already approved for long-term use in infants and adults, might represent a promising therapy for the treatment of ARB and other bestrophinopathies resulting from missense mutations in BEST1.

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Section: Resultssupporting

confidence: 62%

Restoration of mutant bestrophin-1 expression, localisation and function in a polarised epithelial cell model

Uggenti

Briant

Streit

et al. 2016

Disease Models &Amp; Mechanisms

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“…It is interesting that the Y227N, but not the Y227C, mutation results in mislocalization of the protein. It was recently reported, however, that different mutations at this position can have disparate effects on the localization of Best1, with Y227N and Y227F being mislocalized and properly localized, respectively (Doumanov et al, 2013). Although Y227N and Y227C are mutations thought to be causal for disease, Y227F has, to date, not been reported in association with disease.…”

Section: Discussionmentioning

confidence: 99%

Disease-causing mutations associated with four bestrophinopathies exhibit disparate effects on the localization, but not the oligomerization, of Bestrophin-1

Johnson

Lee

Chadburn

et al. 2014

Experimental Eye Research

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BEST1 encodes Bestrophin-1 (Best1), a homo-oligomeric, integral membrane protein localized to the basolateral plasma membrane of the retinal pigment epithelium. Mutations in BEST1 cause five distinct retinal degenerative diseases, including adult vitelliform macular dystrophy (AVMD), autosomal recessive bestrophinopathy (ARB), autosomal dominant vitreoretinochoroidopathy (ADVIRC), and retinitis pigmentosa (RP). The mechanisms underlying these diseases and why mutations cause one disease over another are, for the most part, unknown. To gain insights into these four diseases, we expressed 28 Best1 mutants fused to YFP in polarized MDCK monolayers and, via confocal microscopy and immunofluorescence, live-cell FRET, and reciprocal co-immunoprecipitation experiments, screened these mutants for defects in localization and oligomerization. All 28 mutants exhibited comparable FRET efficiencies to and co-immunoprecipitated with WT Best1, indicating unimpaired oligomerization. RP- and ADVIRC-associated mutants were properly localized to the basolateral plasma membrane of cells, while two AVMD and most ARB mutants were mislocalized. When co-expressed, all mislocalized mutants caused mislocalization of WT Best1to intracellular compartments. Our current and past results indicate that mislocalization of Best1 is not an absolute feature of any individual bestrophinopathy, occurring in AVMD, BVMD, and ARB. Furthermore, some ARB mutants that do not also cause dominant disease cause mislocalization of Best1, indicating that mislocalization is not a cause of disease, and that absence of Best1 activity from the plasma membrane is tolerated. Lastly, we find that the ARB truncation mutants L174Qfs*57 and R200X can form oligomers with WT Best1, indicating that the first ~174 amino acids of Best1 are sufficient for oligomerization to occur.

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“…Cells from this line can reach their polarization just for five–six days growing on transwell filters, a relatively short period, making them good model for investigation of protein sorting and cell polarization. [ 15 ]…”

Section: Resultsmentioning

confidence: 99%

Changes in the functional characteristics of tumor and normal cells after treatment with extracts of white dead-nettle

Veleva

Petkova

Moskova-Doumanova

et al. 2014

Biotechnology & Biotechnological Equipment

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Lamium album L. is a perennial herb widely used in folk medicine. It possesses a wide spectrum of therapeutic activities (anti-inflammatory, astringent, antiseptic, antibiotic, antispasmodic, antioxidant and anti-proliferative). Preservation of medicinal plant could be done by in vitro propagation to avoid depletion from their natural habitat. It is important to know whether extracts from L. album plants grown in vitro possess similar properties as extracts from plants grown in vivo. For these reasons, it is important to examine changes in the composition of secondary metabolites during in vitro cultivation of the plant and how they affect the biological activity.We used A549 human cancer cell line and normal kidney epithelial cells MDCKII (Madin–Darby canine kidney cells II) as controls in assessing the anti-cancer effect of plant extracts. To elucidate changes in some key functional characteristics, adhesion test, MTT (3-(4,5-dimethylthiazol-2-yl)-2-5-diphenyl tetrazolium bromide), transepithelial resistance (TER), immunofluorescence staining and trypan blue exclusion test were performed.Methanol and chloroform extracts of in vivo and in vitro propagated plants affected differently cancerous and non-cancerous cells. The most pronounced differences were observed in the morphological analysis and in the cell adhesive properties. We also detected suppressed epithelial transmembrane electrical resistance of MDCK II cells, by treatment with plant extracts, compared to non-treated MDCK II cells. A549 cells did not polarize under the same conditions. Altered organization of actin filaments in both cell types were noticed suggesting that extracts from L. album L. change TER and actin filaments, and somehow may block cell mechanisms, leading to the polarization of MDCK II cells.

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Disease-Causing Mutations in BEST1 Gene Are Associated with Altered Sorting of Bestrophin-1 Protein

Cited by 13 publications

References 52 publications

Restoration of mutant bestrophin-1 expression, localisation and function in a polarised epithelial cell model

Restoration of mutant bestrophin-1 expression, localisation and function in a polarised epithelial cell model

Disease-causing mutations associated with four bestrophinopathies exhibit disparate effects on the localization, but not the oligomerization, of Bestrophin-1

Changes in the functional characteristics of tumor and normal cells after treatment with extracts of white dead-nettle

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