Transcriptional activator that binds with high affinity to the T-cell enhancer motif 5'-AACAAAG-3' motif (PubMed:8404853). Required for IL17A-producing Vgamma2-positive gamma-delta T-cell maturation and development, via binding to regulator loci of RORC to modulate expression (PubMed:23562159). Involved in skeletal myoblast differentiation by promoting gene expression of CALD1 (PubMed:26291311). Interacts with UBE2I. Interacts with HDAC1; interaction inhibits the transcriptional activator activity. Expressed in both gamma-delta T-cells and Cd4+ Cd8+ double-positive (DP) alpha-beta T-cells (PubMed:17218525). Expressed in the ovaries and the thymus (PubMed:8404853, PubMed:17218525). Expressed in molar and incisor tooth germs at 14.5 dpc. 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 (By similarity). Acetylation by KAT5 abolishes the interaction between SOX4 and HDAC1 and switches SOX4 into a transcriptional activator (By similarity). In T-cell-specific knockout mice, loss of mature Il17a-producing Vgamma2-positive gamma-delta T-cells and reduction of Rorc expression in immature Vgamma2-positive thymocytes (PubMed:23562159). In a mouse model for psoriasis, dermal inflammation induced by skin application of TLR7 synthetic ligand imiquimod is substantially reduced due to the absence of Vgamma2-positive gamma-delta T-cells (PubMed:23562159). May be involved in the T-cell immune response in the psoriasis-like disease which is induced in mice by the application of the TLR7 ligand Imiquimod to skin.