TF Info Page for XBP1 (bZIP)


Assessment Binding Mode Motif Status Notes Comments
Known motif 1 Monomer or homomultimer High-throughput in vitro


Description: X-box binding protein 1 [Source:HGNC Symbol;Acc:HGNC:12801]
Entrez Summary This gene encodes a transcription factor that regulates MHC class II genes by binding to a promoter element referred to as an X box. This gene product is a bZIP protein, which was also identified as a cellular transcription factor that binds to an enhancer in the promoter of the T cell leukemia virus type 1 promoter. It may increase expression of viral proteins by acting as the DNA binding partner of a viral transactivator. It has been found that upon accumulation of unfolded proteins in the endoplasmic reticulum (ER), the mRNA of this gene is processed to an active form by an unconventional splicing mechanism that is mediated by the endonuclease inositol-requiring enzyme 1 (IRE1). The resulting loss of 26 nt from the spliced mRNA causes a frame-shift and an isoform XBP1(S), which is the functionally active transcription factor. The isoform encoded by the unspliced mRNA, XBP1(U), is constitutively expressed, and thought to function as a negative feedback regulator of XBP1(S), which shuts off transcription of target genes during the recovery phase of ER stress. A pseudogene of XBP1 has been identified and localized to chromosome 5. [provided by RefSeq, Jul 2008]
Ensembl ID: ENSG00000100219
External Link: CisBP
Interpro IPR004827; ;
Protein Domain: ENSP00000216037
Protein Domain: ENSP00000384295
Protein Domain: ENSP00000385162
Protein: ENSP00000216037DBD: bZIPOther:
Protein: ENSP00000384295DBD: bZIPOther:
Protein: ENSP00000385162DBD: bZIPOther:

Previous Annotations

Source Annotation
TF-CAT classification TF Gene_DNA-Binding
sequence-specific_DNA Binding
Vaquerizas 2009 TF classification
"a" Has direct evidence of TF function;
"b" Has evidence for an orthologous TF;
"c" contains likely DBDs, but has no functional evidence;
"x" is an unlikely TF such as predicted gene, genes with likely non-specific DBDs or that have function outside transcription;
"other" category contains proteins without clear DBDs they curated from external sources.
CisBP considers it as a TF? Yes
TFclass considers it as a TF? Yes
Has GO:0003700 "transcription factor activity, sequence-specific DNA binding" Yes
GO-Info GO:0000981
sequence-specific DNA binding RNA polymerase II transcription factor activity
IEA - GO_REF:0000019
sequence-specific DNA binding transcription factor activity
IDA - PMID:1903538, PMID:8657566
Initial Assessment
1a1 Protein has a high confidence PWM (HT-SELEX, PBM or B1H model) or there is a crystal structure that supports sequence specific DNA binding;
1a2 There is high confidence data for a close ortholog (as defined in CisBP);
2a1 There is lower confidence direct evidence, such as a Jaspar, Hocomoco or Transfac model;
2a2 There is lower confidence evidence for an close ortholog;
3a There is decent circumstantial evidence for its role as a TF or not;
4a Two or more datasets predict it as a TF;
5a One of the source datasets predicts is as a TF
1a1, Direct HQ evidence
TF has conditional DNA-binding requirements


Published Motif Data

Source Annotation Motif Evidence
TransfacTransfacLicense requiredDirect
TransfacTransfacLicense requiredDirect
TransfacTransfacLicense requiredDirect
PBMDREAM_contestInferred - Xbp1 (96% AA Identity, Mus musculus)
PBMZoo_01Inferred - Xbp1 (96% AA Identity, Mus musculus)


Structure PDB Not_Covered

Experimental History

Method Constructs
Tried in PBM?
(Whether the protein was tried in PBM or not)
Tried in HT-SELEX
(Whether the protein was tried in HT-SELEX or not, and if so, then what kind of clones were tested)
Other Information?
(Tried with another method and failed?)

External Contribution