Human genetic variants disrupt RGS14 nuclear shuttling and regulation of LTP in hippocampal neurons.
Human genetic variants disrupt RGS14 nuclear shuttling and regulation of LTP in hippocampal neurons.
复制标题
DOI：
10.1074/jbc.ra120.016009
复制
发表时间：
2021-01
期刊：
影响因子：
--
通讯作者：
Hepler JR
中科院分区：
文献类型：
--
作者：
Squires KE;Gerber KJ;Tillman MC;Lustberg DJ;Montañez-Miranda C;Zhao M;Ramineni S;Scharer CD;Saha RN;Shu FJ;Schroeder JP;Ortlund EA;Weinshenker D;Dudek SM;Hepler JR
人类基因组包含大量的遗传多样性，作为自然发生的编码变异，然而这些变异对蛋白质功能和生理的影响知之甚少。RGS14是一种抑制海马神经元树突棘突触可塑性的多功能信号蛋白。RGS14也是一种核胞质穿梭蛋白，这表明平衡的核进出口和树突棘定位对RGS14的功能至关重要。我们在人类RGS14的核输出序列（NES）中发现了遗传变异L505R （LR）和R507Q （RQ）。在这里，我们报道了编码LR或RQ的RGS14深刻影响海马神经元的蛋白质功能。RGS14的膜定位受结合的Gαi-GDP调控，而RGS14的核出口受出口蛋白1 （Exportin 1, XPO1）调控。值得注意的是，LR和RQ变体破坏了RGS14与Gαi1-GDP和XPO1的结合，核质平衡，以及抑制长期增强（LTP）的能力。变体LR在细胞核内不可逆地积累，阻止RGS14与Gαi1结合，定位到树突棘，抑制LTP诱导作用，而变体RQ则表现出混合表型。通过CRISPR/Cas9导入小鼠后，RGS14-LR蛋白主要在海马、中央杏仁核、梨状皮质和纹状体等与学习和突触可塑性相关的大脑区域的神经元核中表达。完全缺乏RGS14的小鼠表现出增强的空间学习能力，而携带变异LR的小鼠表现出正常的空间学习能力，这表明RGS14可能在细胞核中具有不同于树突和脊柱的功能。这些发现表明，自然发生的遗传变异可以深刻地改变正常的蛋白质功能，以意想不到的方式影响生理。
The human genome contains vast genetic diversity as naturally occurring coding variants, yet the impact of these variants on protein function and physiology is poorly understood. RGS14 is a multifunctional signaling protein that suppresses synaptic plasticity in dendritic spines of hippocampal neurons. RGS14 also is a nucleocytoplasmic shuttling protein, suggesting that balanced nuclear import/export and dendritic spine localization are essential for RGS14 functions. We identified genetic variants L505R (LR) and R507Q (RQ) located within the nuclear export sequence (NES) of human RGS14. Here we report that RGS14 encoding LR or RQ profoundly impacts protein functions in hippocampal neurons. RGS14 membrane localization is regulated by binding Gαi-GDP, whereas RGS14 nuclear export is regulated by Exportin 1 (XPO1). Remarkably, LR and RQ variants disrupt RGS14 binding to Gαi1-GDP and XPO1, nucleocytoplasmic equilibrium, and capacity to inhibit long-term potentiation (LTP). Variant LR accumulates irreversibly in the nucleus, preventing RGS14 binding to Gαi1, localization to dendritic spines, and inhibitory actions on LTP induction, while variant RQ exhibits a mixed phenotype. When introduced into mice by CRISPR/Cas9, RGS14-LR protein expression was detected predominantly in the nuclei of neurons within hippocampus, central amygdala, piriform cortex, and striatum, brain regions associated with learning and synaptic plasticity. Whereas mice completely lacking RGS14 exhibit enhanced spatial learning, mice carrying variant LR exhibit normal spatial learning, suggesting that RGS14 may have distinct functions in the nucleus independent from those in dendrites and spines. These findings show that naturally occurring genetic variants can profoundly alter normal protein function, impacting physiology in unexpected ways.