This gene encodes a nuclear protein, which colocalizes with mRNA splicing factors and intermediate filament-containing perinuclear networks. This protein has 95% amino acid sequence identity to the mouse Wbp11 protein. It contains two proline-rich regions that bind to the WW domain of Npw38, a nuclear protein, and thus this protein is also called Npw38-binding protein NpwBP. The Npw38-NpwBP complex may function as a component of an mRNA factory in the nucleus.