NDUFS4 deletion triggers loss of NDUFA12 in Ndufs4-/- mice and Leigh syndrome patients: A stabilizing role for NDUFAF2
NDUFS4 deletion triggers loss of NDUFA12 in Ndufs4-/- mice and Leigh syndrome patients: A stabilizing role for NDUFAF2
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DOI：
10.1016/j.bbabio.2020.148213
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发表时间：
2020-08-01
影响因子：
4.3
通讯作者：
Koopman, Werner J. H.
中科院分区：
文献类型：
--
作者：
Adjobo-Hermans, Merel J. W.;de Haas, Ria;Koopman, Werner J. H.
NDUFS 4编码线粒体氧化磷酸化（OXPHOS）复合物I（CI）的辅助亚基，NDUFS 4中的突变诱导Leigh综合征（LS）。LS是一种知之甚少的儿科疾病，以大脑特异性异常和早期死亡为特征。为了研究LS的病理机制，我们在此比较了不同Ndufs 4（-/-）小鼠组织之间的OXPHOS蛋白质组。Ndufs 4（-/-）动物在脑/横膈膜中相对于其他组织（肝/心脏/肾/骨骼肌）显示出显著较低的Cl亚基水平，而其他OXPHOS亚基水平没有降低。NDUFS 4的缺失诱导NDUFA 12辅助亚基的几乎完全缺失，其他Cl亚基水平降低50%，并且特异性Cl组装因子增加。在后者中，NDUFAF 2增加最多。关于NDUFS 4、NDUFA 12和NDUFAF 2，在NDufs 4（-/-）小鼠胚胎成纤维细胞（MEF）和NDUFS 4突变的LS患者细胞中获得了相同的结果。Ndufs 4（-/-）MEF原位含有活性Cl，但蓝色非变性PAGE突出显示NDUFAF 2附着于无活性Cl亚复合物（Cl-830）和更高MW的无活性组装体。在NDUFA 12突变的LS患者细胞中，NDUFA 12的缺失并没有降低NDUFS 4水平，而是触发了NDUFA 2与活动性CI的关联。BN-PAGE显示LS患者成纤维细胞与其他CI亚基编码基因中的突变没有这种关联，其中NDUFAF 2连接到CI-830（NDUFS 1，NDUFV 1突变）或未检测到（NDUFS 7突变）。在酶学和CI计算机结构分析的支持下，我们得出结论，NDUFS 4的缺失诱导NDUFA 12的几乎完全缺失，但反之亦然，并且NDUFAF 2稳定了NDUFS 4（-/-）小鼠和LS患者细胞中的活性CI，这可能与线粒体内膜脂质一致。
Mutations in NDUFS4, which encodes an accessory subunit of mitochondrial oxidative phosphorylation (OXPHOS) complex I (CI), induce Leigh syndrome (LS). LS is a poorly understood pediatric disorder featuring brain-specific anomalies and early death. To study the LS pathomechanism, we here compared OXPHOS proteomes between various Ndufs4(-/-) mouse tissues. Ndufs4(-/-) animals displayed significantly lower CI subunit levels in brain/diaphragm relative to other tissues (liver/heart/kidney/skeletal muscle), whereas other OXPHOS subunit levels were not reduced. Absence of NDUFS4 induced near complete absence of the NDUFA12 accessory subunit, a 50% reduction in other CI subunit levels, and an increase in specific CI assembly factors. Among the latter, NDUFAF2 was most highly increased. Regarding NDUFS4, NDUFA12 and NDUFAF2, identical results were obtained in Ndufs4(-/-) mouse embryonic fibroblasts (MEFs) and NDUFS4-mutated LS patient cells. Ndufs4(-/-) MEFs contained active CI in situ but blue-native-PAGE highlighted that NDUFAF2 attached to an inactive CI subcomplex (CI-830) and inactive assemblies of higher MW. In NDUFA12-mutated LS patient cells, NDUFA12 absence did not reduce NDUFS4 levels but triggered NDUFAF2 association to active CI. BN-PAGE revealed no such association in LS patient fibroblasts with mutations in other CI subunit-encoding genes where NDUFAF2 was attached to CI-830 (NDUFS1, NDUFV1 mutation) or not detected (NDUFS7 mutation). Supported by enzymological and CI in silico structural analysis, we conclude that absence of NDUFS4 induces near complete absence of NDUFA12 but not vice versa, and that NDUFAF2 stabilizes active CI in Ndufs4(-/-) mice and LS patient cells, perhaps in concert with mitochondrial inner membrane lipids.