The protein encoded by this gene is a component of the pre-mRNA-processing factor 19-cell division cycle 5-like (PRP19-CDC5L) protein complex, which activates pre-mRNA splicing and is an integral part of the spliceosome. The encoded protein is also a nuclear localization sequence binding protein, and binds to activation-induced deaminase and is important for antibody diversification. This gene may also be associated with the development of obesity. Alternative splicing results in multiple transcript variants. A pseudogene of this gene has been defined on the X chromosome.