BACKGROUND Phosphatase and tensin homolog (PTEN) negatively regulates downstream protein kinase B signaling, resulting in decreased cellular growth and proliferation. PTEN is mutated in a subset of children with autism spectrum disorder (ASD); however, the mechanism by which specific point mutations alter PTEN function is largely unknown. Here, we assessed how ASD-associated single-nucleotide variations in PTEN (ASD-PTEN) affect function. METHODS We used viral-mediated molecular substitution of human PTEN into Pten knockout mouse neurons and assessed neuronal morphology to determine the functional impact of ASD-PTEN. We employed molecular cloning to examine how PTEN's stability, subcellular localization, and catalytic activity affect neuronal growth. RESULTS We identified a set of ASD-PTEN mutations displaying altered lipid phosphatase function and subcellular localization. We demonstrated that wild-type PTEN can rescue the neuronal hypertrophy, while PTEN H93R, F241S, D252G, W274L, N276S, and D326N failed to rescue this hypertrophy. A subset of these mutations lacked nuclear localization, prompting us to examine the role of nuclear PTEN in regulating neuronal growth. We found that nuclear PTEN alone is sufficient to regulate soma size. Furthermore, forced localization of the D252G and W274L mutations into the nucleus partially restores regulation of soma size. CONCLUSIONS ASD-PTEN mutations display decreased stability, catalytic activity, and/or altered subcellular localization. Mutations lacking nuclear localization uncover a novel mechanism whereby lipid phosphatase activity in the nucleus can regulate mammalian target of rapamycin signaling and neuronal growth.

中文翻译：

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核排除自闭症相关 PTEN 突变使神经元生长失调

背景磷酸酶和张力蛋白同系物(PTEN) 负向调节下游蛋白激酶B 信号，导致细胞生长和增殖减少。PTEN 在一部分自闭症谱系障碍 (ASD) 儿童中发生突变；然而，特定点突变改变 PTEN 功能的机制在很大程度上是未知的。在这里，我们评估了 PTEN (ASD-PTEN) 中与 ASD 相关的单核苷酸变异如何影响功能。方法我们使用病毒介导的人 PTEN 分子替代 Pten 敲除小鼠神经元并评估神经元形态以确定 ASD-PTEN 的功能影响。我们采用分子克隆来检查 PTEN 的稳定性、亚细胞定位和催化活性如何影响神经元生长。结果 我们鉴定了一组 ASD-PTEN 突变，显示出改变的脂质磷酸酶功能和亚细胞定位。我们证明野生型 PTEN 可以挽救神经元肥大，而 PTEN H93R、F241S、D252G、W274L、N276S 和 D326N 未能挽救这种肥大。这些突变的一个子集缺乏核定位，促使我们检查核 PTEN 在调节神经元生长中的作用。我们发现仅核 PTEN 就足以调节体细胞大小。此外，将 D252G 和 W274L 突变强制定位到细胞核中部分恢复了对体细胞大小的调节。结论 ASD-PTEN 突变显示稳定性、催化活性和/或亚细胞定位改变。