NXT1

NXT1, also known as nuclear export factor 1 or transporter 1 (NXT1), is a small protein encoded by the NXT1 gene located on chromosome 1 in humans. It is highly conserved across eukaryotes, with orthologs identified in yeast, Drosophila, and mammals, underscoring its fundamental role in cellular physiology.

The primary function of NXT1 is to facilitate nuclear export of macromolecules by partnering with karyopherin family members such as Crm1 (XPO1). In the heterodimeric complex, NXT1 binds to the nuclear export signal (NES) peptide of cargo proteins and promotes their translocation through the nuclear pore complex. In addition to its role in protein export, NXT1 is implicated in the export of certain RNAs, contributing to gene expression regulation.

NXT1 is ubiquitously expressed, with higher levels in tissues that exhibit rapid cell turnover, such as bone marrow and intestinal epithelium. Post-translational modifications, including phosphorylation, modulate its activity and subcellular localization.

Genetic variants in NXT1 have been associated with neuromuscular disorders. Deletions involving NXT1 can lead to limb girdle muscular dystrophy type 2, while missense mutations are linked to congenital myopathy. Studies have also suggested a role for NXT1 in cancer, where altered expression may influence tumor progression through dysregulated nuclear export.

Ongoing research aims to elucidate the full spectrum of NXT1’s interactions and its potential as a therapeutic target in diseases involving aberrant nucleo-cytoplasmic transport.