A CRM1-Mediated Nuclear Export Signal Is Essential for Cytoplasmic Localization of Neurogenin 3 in Neurons

Abstract

Neurogenin 3 (Ngn3), a proneural gene, regulates dendritogenesis and synaptogenesis in mouse hippocampal neurons. Ngn3 is transiently exported from the cell nucleus to the cytoplasm when neuronal polarity is initiated, suggesting that the nucleo-cytoplasmic transport of the protein is important for its action on neuronal development. In this study, we identified for the first time a functional nuclear export sequence (NES2; 131YIWALTQTLRIA142) in Ngn3. The green fluorescent protein (EGFP)-NES2 fusion protein was localized in the cytoplasm and its nucleo-cytoplasmic shuttling was blocked by the CRM1 specific export inhibitor leptomycin B. Mutation of a leucine residue to alanine (L135A) in the NES2 motif resulted in both cytoplasmic and nuclear localization of the EGFP-NES2 fusion protein and in the nuclear accumulation of ectopic full-length myc-Ngn3. In addition, point mutation of the leucine 135 counteracted the effects of Ngn3 on neuronal morphology and synaptic inputs indicating that the cytoplasmic localization of Ngn3 is important for neuronal development. Pharmacological perturbation of the cytoskeleton revealed that cytoplasmic Ngn3 is associated with microtubules.

The ubiquitin ligase MuRF1 regulates PPARα activity in the heart by enhancing nuclear export via monoubiquitination

“…A.3A. Using standard published procedures (Simon-Areces et al, 2013; Lin et al, 2005; Durchschlag et al, 2004; Brown et al, 2004; Hake et al, 2000), we next examined whether these putative NES1 and NES2 regions were functional, by mutating the Leucine to Alanine in the NES1 and NES2 regions. If NES1 and/or NES2 were actual nuclear export sequences, these mutations would prevent their nuclear export and confirm their role in targeting PPARα for nuclear export in cardiomyocytes.…”

Estradiol and the Development of the Cerebral Cortex: An Unexpected Role?

“…Ngn3 is upregulated to stimulate dendritogenesis and synaptogenesis. CRM1 mediates the nucleo-cytoplasmic shuttling of Ngn3, allowing transcriptional change (Simon-Areces et al, 2013 ) (Figures 2 , 3 ). In addition to its effect on proliferation, Wnt signaling utilizes ß-catenin-dependent pathways to differentiate intermediate progenitors into neurons (Clevers, 2018 ).…”

Identifying candidate genes for 2p15p16.1 microdeletion syndrome using clinical, genomic, and functional analysis

“…Nevertheless, several deletions involving individual genes or smaller numbers of genes were reported (2)(3)(4)(5)(8)(9)(10) XPO1 (also known as CRM1) is a nuclear export receptor that exports approximately 200 different cargo molecules (e.g., proteins, rRNA, small nuclear RNA [snRNA], miR, and specific mRNAs) from the nucleus to the cytoplasm. This includes molecules required for correct neuronal positioning during development (20) or synaptogenesis (21). REL (also known as c-Rel) is a transcription factor and a key component of the NF-κB pathway with a role in synaptic plasticity, neurogenesis, and differentiation (22,23).…”