PT  - JOURNAL ARTICLE
AU  - Katherine E Squires
AU  - Kyle J Gerber
AU  - Matthew C Tillman
AU  - Daniel J Lustberg
AU  - Carolina Montañez-Miranda
AU  - Meilan Zhao
AU  - Suneela Ramineni
AU  - Christopher D Scharer
AU  - Feng-jue Shu
AU  - Jason P Schroeder
AU  - Eric A Ortlund
AU  - David Weinshenker
AU  - Serena M Dudek
AU  - John R Hepler
TI  - Human genetic variants disrupt RGS14 nuclear shuttling and regulation of LTP in hippocampal neurons
AID  - 10.1101/2020.09.10.289991
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.09.10.289991
4099  - http://biorxiv.org/content/early/2020/09/10/2020.09.10.289991.short
4100  - http://biorxiv.org/content/early/2020/09/10/2020.09.10.289991.full
AB  - The human genome contains vast genetic diversity in the form of 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 carrying LR or RQ profoundly impacts protein functions in hippocampal neurons and brain. Following nuclear import, RGS14 nuclear export is regulated by Exportin 1 (XPO1/CRM1). Remarkably, LR and RQ variants disrupt RGS14 binding to Gαi1-GDP and XPO1, nucleocytoplasmic equilibrium, and capacity to inhibit LTP. Variant LR accumulates irreversibly in the nucleus, preventing RGS14 binding to G proteins, 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.Competing Interest StatementThe authors have declared no competing interest.