WW Domain Binding Protein 11 (WBP11)

WBP11 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. Npw38 and NpwBP are colocalized in the same subnuclear region. Coimmunoprecipitation experiments confirmed the association between Npw38 and NpwBP, which were expressed as epitope-tagged forms in COS7 cells. NpwBP is a physiological ligand of Npw38 and that the Npw38-NpwBP complex may function as a component of an mRNA factory in the nucleus.