Sequence-specific RNA-binding protein probably involved in pre-mRNA splicing. In vitro, can complement efficiently splicing-deficient mammalian SRSF7-depleted HeLa cell extract. Component of the spliceosome. Interacts with AFC2, RS2Z33 and RNU1. Shuttling between nucleolus, nucleoplasm and cytoplasm surrounding the nucleus. Nucleolus localization is dependent on phosphorylation state. Expressed in primary and lateral roots, stems, petioles, abaxial and adaxial epidermis cells, trichomes, unopened flowers, anther filaments, anthers, stigma, pollen, pollen tube, ovule funiculi, integuments, embryo sac and developing seeds. Extensively phosphorylated on serine residues in the RS domain. Phosphorylated by AFC2. Belongs to the splicing factor SR family. RSZ subfamily.