SATB1 (special AT-rich binding protein 1) is essential for T-cell development, growth and metastasis of multitype tumours in addition to its role as a global chromatin organizer and gene expression regulator. All of this function require of its DNA binding ability. SATB1 binds DNA at specific sites, the nuclear matrix attachment regions (MARs) which have a physical unwinding property and affinity for this protein. SATB1 exhibits a cage-like network and organizes higher order chromatin loops into distinct domains via anchoring MARs to the nuclear matrix.

SATB1 is comprised by ULD and CUTL domains at the N terminus, a homeodomain (HD) at the C terminus, and a CUT1-CUT2 tandem in the center. High affinity DNA-binding is achieved through tetramer formation, which occurs through the N-terminal ULD. Structural domains comprising this superfamily share the structure of the CULT domain of SATB proteins, essential for the contact between DNA and SATB1. This CULT (CUT repeat-like domain), was named after the remarkable structure similarity it shares with the CUT1 domain. Overall, the tetrameric SATB1 binds one or two DNA fragments via coordination of the CUTL domain, the CUT1-CUT2 tandem, and HD domains to act as a global chromatin organizer and gene expression regulator PMID:25124042.