Variants in the ANK3 gene encoding ankyrin-G are associated with neurodevelopmental disorders, including intellectual disability, autism, schizophrenia, and bipolar disorder. However, no upstream regulators of ankyrin-G at synapses are known. Here, we show that ankyrin-G interacts with Usp9X, a neurodevelopmental-disorder-associated deubiquitinase (DUB). Usp9X phosphorylation enhances their interaction, decreases ankyrin-G polyubiquitination, and stabilizes ankyrin-G to maintain dendritic spine development. In forebrain-specific Usp9X knockout mice (Usp9X-/Y), ankyrin-G as well as multiple ankyrin-repeat domain (ANKRD)-containing proteins are transiently reduced at 2 but recovered at 12 weeks postnatally. However, reduced cortical spine density in knockouts persists into adulthood. Usp9X-/Y mice display increase of ankyrin-G ubiquitination and aggregation and hyperactivity. USP9X mutations in patients with intellectual disability and autism ablate its catalytic activity or ankyrin-G interaction. Our data reveal a DUB-dependent mechanism of ANKRD protein homeostasis, the impairment of which only transiently affects ANKRD protein levels but leads to persistent neuronal, behavioral, and clinical abnormalities.

中文翻译：

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Usp9X在树突棘发育过程中控制锚蛋白重复域蛋白稳态。

编码锚蛋白-G的ANK3基因变异与神经发育障碍有关，包括智力残疾，自闭症，精神分裂症和躁郁症。但是，尚不知道突触中锚蛋白-G的上游调节剂。在这里，我们显示锚蛋白G与Usp9X（一种与神经发育障碍相关的去泛素酶（DUB））相互作用。Usp9X磷酸化增强了它们的相互作用，减少了锚蛋白G的泛素化，并稳定了锚蛋白G来维持树突状脊柱的发育。在前脑特异性Usp9X基因敲除小鼠（Usp9X- / Y）中，含锚蛋白G和多个含锚蛋白重复结构域（ANKRD）的蛋白质在2时瞬时减少，但在出生后12周时恢复。然而，基因敲除的皮质脊柱密度降低一直持续到成年期。Usp9X- / Y小鼠显示出锚蛋白-G泛素化，聚集和过度活跃。具有智力障碍和自闭症的患者中的USP9X突变会消除其催化活性或锚蛋白-G相互作用。我们的数据揭示了ANKRD蛋白稳态的一种DUB依赖性机制，其损害仅短暂地影响ANKRD蛋白水平，但导致持续的神经元，行为和临床异常。