Transcriptional activator that binds with high affinity to the T-cell enhancer motif 5'-AACAAAG-3' motif (PubMed:30661772). Required for IL17A-producing Vgamma2-positive gamma-delta T-cell maturation and development, via binding to regulator loci of RORC to modulate expression (By similarity). Involved in skeletal myoblast differentiation by promoting gene expression of CALD1 (PubMed:26291311). Interacts with UBE2I (PubMed:16631117). Interacts with HDAC1; interaction inhibits the transcriptional activator activity (PubMed:16631117). Testis, brain, and heart. The 9aaTAD motif is a transactivation domain present in a large number of yeast and animal transcription factors. Acetylation at Lys-95 by KAT5 promotes the transcription activator activity and is required during myoblast differentiation (PubMed:26291311). Acetylation by KAT5 abolishes the interaction between SOX4 and HDAC1 and switches SOX4 into a transcriptional activator (PubMed:26291311). The disease is caused by variants affecting the gene represented in this entry.