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 Björn, 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
Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent 9000, Belgium.
Department of Pediatrics, Radboud University Medical Center, Nijmegen 6500 HB, the Netherlands; Department of Human Genetics, Radboud University Medical Center, Nijmegen 6500 HB, the Netherlands.
Am J Hum Genet. 2017 Feb 2;100(2):216-227. doi: 10.1016/j.ajhg.2016.12.010. Epub 2017 Jan 5.
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 E1 and A subunits, respectively, of the V 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.
V型质子（H）ATP酶（V-ATP酶）的缺陷会损害膜封闭区室的酸化及细胞内运输，这些区室包括分泌颗粒、内体和溶酶体。对五个患有轻度至重度皮肤松弛症、面部畸形特征和心肺受累的家庭进行全外显子组测序，发现ATP6V1E1和ATP6V1A存在双等位基因错义突变，这两个基因分别编码异源多聚体V-ATP酶复合物V结构域的E1和A亚基。结构建模表明，所有替代都影响关键残基以及亚基间或亚基内的相互作用。此外，复合物组分析（一种结合蓝色非变性凝胶电泳和液相色谱串联质谱的方法）表明，它们会干扰V-ATP酶复合物的组装或稳定性。蛋白质糖基化受到不同程度的影响。布雷菲德菌素A处理后逆行运输延迟以及高尔基体异常肿胀和碎片化证明了囊泡运输异常。除了显示弹性纤维减少和碎片化（皮肤松弛症的组织病理学特征）外，真皮的透射电子显微镜检查还显示胶原纤维的结构和组织有明显变化。我们的研究结果扩展了代谢性皮肤松弛症综合征的临床和分子谱，并进一步将有缺陷的细胞外基质组装与V-ATP酶复合物基因缺陷导致的蛋白质加工和细胞运输故障联系起来。
