UNIPROT #

Q01826

PROTEIN NAME

SATB1

SYNONYMS

DNA binding protein SATB1 antibody; DNA-binding protein SATB1 antibody; SATB homeobox 1 antibody; SATB1 antibody; SATB1_HUMAN antibody; Special AT rich sequence binding protein 1 (binds to nuclear matrix/scaffold associating DNA) antibody; Special AT rich sequence binding protein 1 antibody; Special AT-rich sequence-binding protein 1 antibody

SEQUENCE SIMILARITIES

Belongs to the CUT homeobox family.

TISSUE SPECIFICITY

Expressed predominantly in thymus.

POST-TRANSLATIONAL MODIFICATION

Sumoylated. Sumoylation promotes cleavage by caspases.; Phosphorylated by PKC. Acetylated by PCAF. Phosphorylated form interacts with HDAC1, but unphosphorylated form interacts with PCAF. DNA binding properties are activated by phosphorylation and inactivated by acetylation. In opposition, gene expression is down-regulated by phosphorylation but up-regulated by acetylation.; Cleaved at Asp-254 by caspase-3 and caspase-6 during T-cell apoptosis in thymus and during B-cell stimulation. The cleaved forms cannot dimerize and lose transcription regulation function because of impaired DNA and chromatin association.

SUBCELLULAR LOCATION

Nucleus matrix, Nucleus.

FUNCTION

The homeoproteins CCAAT displacement protein (CDP) and special AT-rich sequence binding protein 1 (SATB1) are transcriptional repressors of many cellular genes, and they participate in cell development and cell type differentiation. SATB1 is expressed primarily in thymocytes, and, like CDP, it also contains a distinct homeobox DNA-binding domain that is essential for DNA binding. SATB1 and CDP interact through these homeodomains and synergistically function as mediators of gene expression. SATB1 contains an additional domain that has a higher affinity for DNA and specifically facilitates the direct association between SATB1 and the nuclear matrix attachment regions (MARs) of DNA. MARs are specific DNA sequences that bind to the nuclear matrix and form the base of chromosomal loops that organize the chromosomes and regulate DNA transcription and replication within the nucleus. The association of SATB1 with the core unwinding element within the base-unpairing region of MARs requires both the MAR and homeobox binding domains of SATB1.