Anti-SUB1 regulator of transcription antibodies are used for the immunodetection of the protein encoded by the SUB1 gene. In humans, the canonical protein has a reported length of 127 amino acid residues and a mass of 14.4 kDa. Its subcellular localization is in the nucleus. A member of the Transcriptional coactivator PC4 protein family, it is reported to be a general coactivator that functions cooperatively with TAFs and mediates functional interactions between upstream activators and the general transcriptional machinery. Post-translational modifications have been described, including phosphorylation. Other names for this target antigen include PC4, activated RNA polymerase II transcriptional coactivator p15, SUB1 homolog, transcriptional regulator, activated RNA polymerase II transcription cofactor 4, and P15. Gene orthologs have been identified in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.