NXT1 Human

NXT1 is a 140-amino acid protein that shares significant similarity with Nuclear Transport Factor 2 (NTF2), being 26% identical and 43% similar . It functions as a nuclear export factor in both RAN (Ras-related nuclear protein)- and CRM1 (required for chromosome region maintenance)-dependent pathways . The protein is predominantly expressed in the nucleus and is located in the nuclear envelope, excluding the nucleoli .

NXT1 forms a heterodimer with the TAP protein (also known as NXF1), which is essential for the export of mRNA from the nucleus to the cytoplasm . This complex is conserved from yeast to humans, indicating its fundamental role in cellular processes .

NXT1 binds directly to RAN-GTP, a small GTPase involved in the transport of proteins and RNA across the nuclear envelope . It shuttles between the nucleus and the cytoplasm, facilitating the export of U1 snRNA, tRNA, and mRNA . The NXT1-TAP complex can functionally complement its homologous complex, Mex67/Mtr2, in yeast .

Research has shown that NXT1 strongly stimulates the export of U1 snRNA in RAN- and CRM1-dependent pathways and the export of tRNA and mRNA in a CRM1-independent pathway . This makes it a critical component in the regulation of gene expression and cellular function.

Recombinant human NXT1 protein, fused to a His-tag at the N-terminus, is expressed in E. coli and purified using conventional chromatography . This recombinant form is used in various research applications to study its function and interactions with other proteins.

Mutations or dysregulation of the NXT1 gene can be associated with various diseases, including hypoinsulinemic hypoglycemia with hemihypertrophy and hepatic tuberculosis . Understanding the function and regulation of NXT1 can provide insights into these conditions and potential therapeutic targets.