May play a role in pre-mRNA splicing as component of the spliceosome (PubMed:25599396). Acts as an important regulator of the cell cycle that participates in the maintenance of genome integrity. During cell cycle progression in embryonic fibroblast, prevents replication fork collapse, double-strand break formation and cell cycle checkpoint activation. Controls mitotic cell cycle progression and cell survival in rapidly proliferating intestinal epithelium and embryonic stem cells. During the embryo preimplantation, controls different aspects of M phase. During early oocyte growth, plays a role in oocyte survival by preventing chromosomal breaks formation, activation of TP63 and reduction of transcription (By similarity). Component of the XAB2 complex, a multimeric protein complex composed of XAB2, PRPF19, AQR, ZNF830, ISY1, and PPIE; this complex binds preferentially to RNA. Interacts with XAB2 (PubMed:17981804). Identified in a pentameric intron-binding (IB) complex composed of AQR, XAB2, ISY1, ZNF830 and PPIE that is incorporated into the spliceosome as a preassembled complex (PubMed:25599396). The IB complex does not contain PRPF19 (PubMed:25599396). Excluded from nucleolus. Phosphorylated in response to DNA damage by the cell cycle checkpoint kinases ATR/ATM.