Browsing by Author "Gardeitchik, Thatjana"

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    Further characterization of ATP6V0A2-related autosomal recessive cutis laxa
    (SPRINGER, 2012-01-01) Fischer, Bjoern; Dimopoulou, Aikaterini; Egerer, Johannes; Gardeitchik, Thatjana; Kidd, Alexa; Jost, Dominik; Kayserili, Hulya; Alanay, Yasemin; Tantcheva-Poor, Iliana; Mangold, Elisabeth; Daumer-Haas, Cornelia; Phadke, Shubha; Peirano, Reto I.; Heusel, Julia; Desphande, Charu; Gupta, Neerja; Nanda, Arti; Felix, Emma; Berry-Kravis, Elisabeth; Kabra, Madhulika; Wevers, Ron A.; van Maldergem, Lionel; Mundlos, Stefan; Morava, Eva; Kornak, Uwe
    Autosomal recessive cutis laxa (ARCL) syndromes are phenotypically overlapping, but genetically heterogeneous disorders. Mutations in the ATP6V0A2 gene were found to underlie both, autosomal recessive cutis laxa type 2 (ARCL2), Debr, type, and wrinkly skin syndrome (WSS). The ATP6V0A2 gene encodes the a2 subunit of the V-type H+-ATPase, playing a role in proton translocation, and possibly also in membrane fusion. Here, we describe a highly variable phenotype in 13 patients with ARCL2, including the oldest affected individual described so far, who showed strikingly progressive dysmorphic features and heterotopic calcifications. In these individuals we identified 17 ATP6V0A2 mutations, 14 of which are novel. Furthermore, we demonstrate a localization of ATP6V0A2 at the Golgi-apparatus and a loss of the mutated ATP6V0A2 protein in patients' dermal fibroblasts. Investigation of brefeldin A-induced Golgi collapse in dermal fibroblasts as well as in HeLa cells deficient for ATP6V0A2 revealed a delay, which was absent in cells deficient for the ARCL-associated proteins GORAB or PYCR1. Furthermore, fibroblasts from patients with ATP6V0A2 mutations displayed elevated TGF-beta signalling and increased TGF-beta 1 levels in the supernatant. Our current findings expand the genetic and phenotypic spectrum and suggest that, besides the known glycosylation defect, alterations in trafficking and signalling processes are potential key events in the pathogenesis of ATP6V0A2-related ARCL.
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    Mutations in ATP6V1E1 or ATP6V1A Cause Autosomal-Recessive Cutis Laxa
    (CELL PRESS, 2017-01-01) Van Damme, Tim; Gardeitchik, Thatjana; Mohamed, Miski; Guerrero-Castillo, Sergio; Freisinger, Peter; Guillemyn, Brecht; Kariminejad, Ariana; Dalloyaux, Daisy; Van Kraaij, Sanne; Lefeber, Dirk J.; Syx, Delfien; Steyaert, Wouter; De Rycke, Riet; Hoischen, Alexander; Kamsteeg, Erik-Jan; Wong, Sunnie Y.; van Scherpenzeel, Monique; Jamali, Payman; Brandt, Ulrich; Nijtmans, Leo; Korenke, G. Christoph; Chung, Brian H. Y.; Mak, Christopher C. Y.; Hausser, Ingrid; Kornak, Uwe; Fischer-Zirnsak, Bjorn; Strom, Tim M.; Meitinger, Thomas; Alanay, Yasemin; Utine, Gulen E.; Leung, Peter K. C.; Ghaderi-Sohi, Siavash; Coucke, Paul; Symoens, Sofie; De Paepe, Anne; Thiel, Christian; Haack, Tobias B.; Malfait, Fransiska; Morava, Eva; Callewaert, Bert; Wevers, Ron A.
    Defects of the V-type proton (H+) ATPase (V-ATPase) impair acidification and intracellular trafficking of membrane-enclosed compartments, including secretory granules, endosomes, and lysosomes. Whole-exome sequencing in five families affected by mild to severe cutis laxa, dysmorphic facial features, and cardiopulmonary involvement identified biallelic missense mutations in ATP6V1E1 and ATP6V1A, which encode the El and A subunits, respectively, of the V-1 domain of the heteromultimeric V-ATPase complex. Structural modeling indicated that all substitutions affect critical residues and inter- or intrasubunit interactions. Furthermore, complexome profiling, a method combining blue-native gel electrophoresis and liquid chromatography tandem mass spectrometry, showed that they disturb either the assembly or the stability of the V-ATPase complex. Protein glycosylation was variably affected. Abnormal vesicular trafficking was evidenced by delayed retrograde transport after brefeldin A treatment and abnormal swelling and fragmentation of the Golgi apparatus. In addition to showing reduced and fragmented elastic fibers, the histopathological hallmark of cutis laxa, transmission electron microscopy of the dermis also showed pronounced changes in the structure and organization of the collagen fibers. Our findings expand the clinical and molecular spectrum of metabolic cutis laxa syndromes and further link defective extracellular matrix assembly to faulty protein processing and cellular trafficking caused by genetic defects in the V-ATPase complex.