Component of the TREX-2 complex (transcription and export complex 2), a muliprotein complex that 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 (PubMed:19843313). Interacts with SAC3A, EER5 and CML19 (PubMed:19843313). Interacts with UCH1 and UCH2 (PubMed:22951400). Apparent concentration to the nuclear periphery. No visible phenotype. Sac3a, sac3b and sac3c triple mutants show no visible phenotype. Belongs to the SAC3 family.