scaffold attachment factor B1; SAF-B; SAF-B1; HSP27 estrogen response element-TATA box-binding protein; HSP27 ERE-TATA-binding protein (SAFB, HAP, HET, SAFB1)

Function

• binds to scaffold/matrix attachment region (S/MAR) DNA & forms a molecular assembly point to allow the formation of a 'transcriptosomal' complex (consisting of SR proteins & RNA polymerase 2) coupling transcription & RNA processing
• can function as an estrogen receptor corepressor
• can also bind to the HSP27 promoter & decrease its transcription
• when associated with RBMX, binds to & stimulates transcription from the SREBF1 promoter (putative)
• can inhibit cell proliferation
• sumoylated by PIAS1 with SUMO1 & SUMO2/3
• desumoylated by SENP1
• sumoylation is required for transcriptional repressor activity
• interacts with KHDRBS3, POLR2A, SAFB2 or SFRS1, SFRS9 & TRA2B/SFRS10 (putative)
• interacts with isoform 1 & isoform 2 of SRPK1 & inhibits its activity
• interacts with RBMX (putative)

Structure

• monomer; can form homodimers
• contains 1 RRM domain (RNA recognition motif)
• contains 1 SAP domain

Compartment

nucleus

Expression

• ubiquitous
• expressed at high levels in the CNS
• expressed at low levels in the liver
• expressed in a wide number of breast cancer cell lines

More general terms

• scaffold protein
• nuclear protein
• RNA-binding protein
• phosphoprotein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=6294
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:6294
• OMIM: https://mirror.omim.org/entry/602895
• UniProt: http://www.uniprot.org/uniprot/Q15424.html