Component of the SAC3-THP1 complex, which functions in transcription-coupled mRNA export from the nucleus to the cytoplasm. SAC3-THP1 functions in docking export-competent ribonucleoprotein particles (mRNPs) to the nuclear entrance of the nuclear pore complex (nuclear basket), by association with components of the nuclear mRNA export machinery (MEX67-MTR2 and SUB2) in the nucleoplasm and the nucleoporin NUP1 at the nuclear basket. Heterodimer with THP1. The SAC3-THP1 complex interacts with CDC31 and SUS1, and with the mRNA export factor MEX67-MTR2, the TREX complex component SUB2, and the nucleoporin NUP1. SAC3 directly interacts with MEX67, NUP1 and SUB2. Localizes to the nuclear pores. Present with 339 molecules/cell in log phase SD medium. Belongs to the SAC3 family.