Isoform GANP:Essential for the generation of high-affinity B-cells against T-cell-dependent antigens by affecting somatic hypermutation at the IgV-regions. May have stimulation-dependent DNA primase activity that would generate extra RNA primers in very rapidely proliferating cells and would support clonal expansion of differentiating B-cells By similarity. Involved in the nuclear export of poly(A)-containing mRNAs by acting as a scaffold for the TREX-2 complex. The TREX-2 complex functions in docking export-competent ribonucleoprotein particles (mRNPs) to the nuclear entrance of the nuclear pore complex (nuclear basket). TREX-2 participates in mRNA export and accurate chromatin positioning in the nucleus by tethering genes to the nuclear periphery. Isoform MCM3AP:Acetyltransferase targeting MCM3. Inhibits initiation of DNA replication, but not elongation.