general transcription factor II-I; GTFII-I; TFII-I; Bruton tyrosine kinase-associated protein 135; BAP-135; BTK-associated protein 135; SRF-phox1-interacting protein; SPIN; Williams-Beuren syndrome chromosomal region 6 protein (GTF2I, BAP135, WBSCR6)

Function

• initiator element-dependent basal transcription factor
• substitutes for TFIIA
• interacts with the basal transcription machinery by coordinating the formation of a multiprotein complex at the C-FOS promoter, & linking specific signal responsive activator complexes
• promotes the formation of stable high-order complexes of SRF & phox1 & 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) & an upstream E-box
• required for the formation of functional ARID3A DNA-binding complexes & for activation of immunoglobulin heavy-chain transcription upon B-lymphocyte activation
• transiently phosphorylated on tyrosine residues by BTK in response to B-cell receptor cross-linking
• sumoylated
• associates with the PH domain of Bruton's tyrosine kinase (BTK)
• may be a component of a BHC histone deacetylase complex

Structure

• homodimer (putative)
• interacts with SRF & phox1
• belongs to the TFII-I family
• contains 6 GTF2I-like repeats

Compartment

cytoplasm, nucleus (putative)

Alternative splicing

named isoforms=4

Expression

• ubiquitous
• isoform 1 is expressed in fetal brain > adult brain, muscle, & lymphoblasts > other adult tissues
• other isoforms are equally expressed in all adult tissues

Pathology

• haploinsufficiency of GTF2I may be the cause of certain cardiovascular & musculo-skeletal abnormalities observed in Williams-Beuren syndrome

More general terms

• general transcription factor (basal transcription factor, transcription initiation factor)
• phosphoprotein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=2969
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:2969
• OMIM: https://mirror.omim.org/entry/601679
• UniProt: http://www.uniprot.org/uniprot/P78347.html