Scaffold Attachment Factor B2 (SAFB2)

SAFB2 encodes a deduced 953-amino acid protein with 75% homology to SAFB. Both SAFB and SAFB2 contain a highly conserved SAF box and RRM domain and both contain a nuclear localization signal. SAFB2 functions as an estrogen receptor corepressor and that its overexpression results in inhibition of proliferation. SAFB and SAFB2 interact directly through a C-terminal domain, resulting in additive repression activity. Whereas SAFB is exclusively nuclear, SAFB2 is found in the cytoplasm as well as in the nucleus. Transfection experiments detected interaction between SAFB2 and vinexin, a protein involved in linking signaling to the cytoskeleton. SAFB1 and SAFB2 are crucial repressors for ERα dynamics in association with the nuclear matrix and that their synergistic regulation of ERα mobility is sufficient for inhibiting ERα function.