Y box binding protein 1 is a human protein. Current research is examining its involvement in cancer, and particularly in the metastasis of cancerous cells or prevention thereof.

The deduced 322-amino acid protein contains 4 putative DNA-binding domains, 3 of which are rich in basic amino acids. Two of these basic regions, basic-1 and basic-2, form the double-strand DNA-binding domain of the protein. NSEP1 also has a pro/ser/thr-rich domain and an asp/glu/gln-rich domain, both of which are reminiscent of activation domains. It also contains an octapeptide single-strand DNA-binding motif that shares weak homology with the ribonucleoprotein consensus sequence of RNA-binding proteins.