TFII-I Antibody #4562

TFII-I (also known as SPIN and BAP-135) is a multifunctional transcription factor that facilitates basal transcriptional machinery assembly at the core promotor region, as well as the assembly of the transcriptional activator complex at upstream regulatory sites (1). Four isoforms of TFII-I (alpha, beta, gamma, and delta) form homo- or heteromeric complexes, which may perform different functions on different promoters (1). In B cells, cross-linking of BCR (B cell receptors) leads to TFII-I phosphorylation at Tyr248 by Btk (2). This phosphorylation disrupts the association of Btk and TFII-I and enhances TFII-I transcriptional activity and nuclear localization (2). In nonlymphoid cells, TFII-I is phosphorylated at Tyr248 by Src dependent kinase or JAK2 (3,4). PKG (cGMP-dependent kinase) interacts with and phosphorylates TFII-I at Ser371 and 743, which also promotes TFII-I transcription activity (5). TFII-I activity is also modulated by HDAC3 (Histone Deacetylase 3) through a physical interaction between the two proteins (6).