THOC2 is a 1,478 amino acid nuclear protein that functions as a component of the heteromultimeric THO/TREX (transcription/export) complex, a multi-protein structure consisting of THOC1, THOC2, THOC3, BAT1 and ALY. The THO/TREX complex is recruited to transcribed genes and travels with RNA polymerase II (Pol II) during elongation, coupling elongating Pol II with RNA splicing and export factors. Defects in the protein components of the TREX structure can cause transcription impairment, mRNA export defects and transcription-associated recombination. THOC2, an important component of the TREX complex, exists as two isoforms that are produced by alternative splicing events.