RNA-binding protein involved in modulation of mRNA transcription by Polymerase II (PubMed:16950395). Component of the tRNA-splicing ligase complex and is required for tRNA ligation (PubMed:24870230). May be required for RNA transport (PubMed:24608264). ; (Microbial infection) In case of infection by influenza virus A (IVA), is involved in viral replication (PubMed:21900157).