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TFII I

Function

Interacts with the basal transcription machinery by coordinating the formation of a multiprotein complex at the C-FOS promoter, and linking specific signal responsive activator complexes. Promotes the formation of stable high-order complexes of SRF and PHOX1 and interacts cooperatively with PHOX1 to promote serum-inducible transcription of a reporter gene deriven by the C-FOS serum response element (SRE). Acts as a coregulator for USF1 by binding independently two promoter elements, a pyrimidine-rich initiator (Inr) and an upstream E-box. Required for the formation of functional ARID3A DNA-binding complexes and for activation of immunoglobulin heavy-chain transcription upon B-lymphocyte activation.

Involvement in disease

GTF2I is located in the Williams-Beuren syndrome (WBS) critical region. WBS results from a hemizygous deletion of several genes on chromosome 7q11.23, thought to arise as a consequence of unequal crossing over between highly homologous low-copy repeat sequences flanking the deleted region. Haploinsufficiency of GTF2I may be the cause of certain cardiovascular and musculo-skeletal abnormalities observed in the disease.

Post-translational modifications

Transiently phosphorylated on tyrosine residues by BTK in response to B-cell receptor stimulation. Phosphorylation on Tyr-248 and Tyr-398, and perhaps, on Tyr-503 contributes to BTK-mediated transcriptional activation.

Sumoylated.

Sequence similarities

Belongs to the TFII-I family.

Tissue specificity

Ubiquitous. Isoform 1 is strongly expressed in fetal brain, weakly in adult brain, muscle, and lymphoblasts and is almost undetectable in other adult tissues, while the other isoforms are equally expressed in all adult tissues.

Cellular localization

  • Cytoplasm
  • Nucleus
  • Colocalizes with BTK in the cytoplasm.

Alternative names

  • General transcription factor II-I
  • GTFII-I
  • TFII-I
  • Bruton tyrosine kinase-associated protein 135
  • SRF-Phox1-interacting protein
  • Williams-Beuren syndrome chromosomal region 6 protein
  • BAP-135
  • BTK-associated protein 135
  • SPIN
  • BAP135
  • WBSCR6
  • GTF2I

Target type

Proteins

Molecular weight

112416Da