TOX (thymocyte selection-associated high mobility group (HMG) box protein) is a member of the HMG box family of DNA-binding proteins and likely plays a role in the regulation of T-cell development. It is a 526 amino acid nuclear protein and the expression of TOX is upregulated by pre-T cell receptor (pre-TCR) and TCR activation in immature thymocytes. TOX-mediated positive selection is associated with up-regulation of RUNX3 and is calcineurin dependent. TOX-dependent transition to the CD4+CD8 stage is required for development of class II major histocompatibility complex-specific T cells.
Thymocyte selection-associated high mobility group box protein TOX; Thymus high mobility group box protein TOX; TOX1