XBP1 Gene: Structure, Function, and Clinical Significance
A comprehensive overview of the X-box binding protein 1 gene, its role in the unfolded protein response, associated diseases, and expression patterns.
Gene Information Card
| Symbol | XBP1 |
|---|---|
| Full Name | X-box binding protein 1 |
| Gene Type | protein coding |
| Chromosomal Location | 22q12.1 |
| NCBI Gene ID | 7494 ncbi.nlm.nih.gov/gene/7494 |
| Ensembl ID | ENSG00000100154 |
| UniProt ID | P17861 |
| OMIM ID | 194355 |
| HGNC ID | 12801 |
| Aliases | TREB5, XBP-1, XBP2 |
Description
The XBP1 gene encodes a basic leucine zipper (bZIP) transcription factor that plays a central role in the unfolded protein response (UPR) by regulating genes involved in protein folding, secretion, and endoplasmic reticulum (ER) stress. It is activated by IRE1-mediated splicing of its mRNA, producing a potent transcriptional activator. XBP1 is essential for the differentiation of plasma cells and the maintenance of secretory tissues, and its dysregulation is implicated in various diseases, including cancer, inflammatory bowel disease, and metabolic disorders.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Inflammatory Bowel Disease (IBD) | XBP1 deficiency in intestinal epithelial cells leads to ER stress and impaired Paneth cell function, contributing to intestinal inflammation. | ClinVar; PMID: 21102463 |
| Multiple Myeloma | XBP1 is constitutively activated in multiple myeloma cells, supporting their survival and proliferation through the UPR. | COSMIC; PMID: 15199142 |
| Hepatocellular Carcinoma | XBP1 overexpression promotes tumor growth and metastasis by regulating the UPR and epithelial-mesenchymal transition. | COSMIC; PMID: 25944712 |
| Breast Cancer | XBP1 splicing is associated with poor prognosis and endocrine resistance in breast cancer, particularly in triple-negative subtypes. | COSMIC; PMID: 21909107 |
| Type 2 Diabetes | XBP1 deficiency in pancreatic beta cells leads to ER stress and apoptosis, contributing to beta-cell failure. | ClinVar; PMID: 17909104 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 12.3 | Medium |
| Pancreas | 9.8 | Medium |
| Small Intestine | 8.5 | Medium |
| Plasma | 5.2 | Low |
| Brain | 4.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HepG2 (liver cancer) | 15.2 | High expression; consistent with liver function |
| MCF7 (breast cancer) | 11.4 | Moderate expression; associated with UPR activation |
| K562 (leukemia) | 7.8 | Low expression; basal UPR activity |
| HeLa (cervical cancer) | 9.1 | Moderate expression; responsive to ER stress |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.397C>T (p.Arg133Ter) | Nonsense | Rare | Loss of function; associated with IBD risk |
| c.548A>G (p.Gln183Arg) | Missense | Rare | Potential functional impact; not well characterized |
| c.−116C>G (promoter) | Regulatory | Common | May affect XBP1 expression; associated with IBD susceptibility |
| Splicing variants (e.g., XBP1s) | Alternative splicing | Common | Constitutive activation; seen in multiple myeloma and other cancers |
Mutation functional classification
Loss of Function (LOF)
Loss-of-function mutations, such as nonsense or frameshift variants, impair XBP1's transcriptional activity, leading to defective UPR and increased ER stress. This is particularly detrimental in secretory cells like intestinal epithelium and pancreatic beta cells, contributing to IBD and diabetes.
Gain of Function (GOF)
Gain-of-function alterations, primarily through aberrant mRNA splicing producing the active XBP1s isoform, enhance UPR signaling and promote cell survival. This is observed in multiple myeloma and other cancers, where XBP1s supports tumor growth.
Dominant Negative (DN)
Dominant-negative effects may occur with certain missense mutations that disrupt DNA binding or dimerization, interfering with wild-type XBP1 function. However, specific dominant-negative variants are not well documented in the literature.
View complete mutation data：
Gene Ontology (GO)
| • DNA-binding transcription factor activity | • RNA polymerase II cis-regulatory region sequence-specific DNA binding |
| • protein dimerization activity | • unfolded protein response |
| • endoplasmic reticulum stress response | • regulation of transcription by RNA polymerase II |
| • positive regulation of transcription by RNA polymerase II | • cellular response to endoplasmic reticulum stress |
| • plasma cell differentiation | • protein folding in endoplasmic reticulum |
Pathways
• Unfolded Protein Response (UPR)
• IRE1-alpha-XBP1 pathway
• ER stress response
• Plasma cell differentiation
• Inflammatory bowel disease signaling
Protein Summary
The XBP1 protein is a 261-amino acid basic leucine zipper (bZIP) transcription factor. Under ER stress, IRE1α splices XBP1 mRNA, removing a 26-nucleotide intron, causing a frameshift that generates the active XBP1s isoform (376 amino acids). XBP1s translocates to the nucleus and regulates genes involved in protein folding, ER-associated degradation (ERAD), lipid synthesis, and secretion. It is critical for the function of secretory cells, including plasma cells, Paneth cells, and hepatocytes. Dysregulation of XBP1 contributes to various pathologies, including cancer, inflammatory diseases, and metabolic disorders.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| XBP1 Knockout HEK293 Cell Line | EDJ-KQ1004 | Human | 7494 | Details Get a Quote |
| STXBP1 Knockout HEK293 Cell Line | EDJ-KQ5866 | Human | 6812 | Details Get a Quote |
| XBP1 Knockout A-549 Cell Line | EDJ-KQ20054 | Human | 7494 | Details Get a Quote |
| XBP1 Knockout HCT 116 Cell Line | EDJ-KQ20055 | Human | 7494 | Details Get a Quote |
| XBP1 Knockout HeLa Cell Line | EDJ-KQ20056 | Human | 7494 | Details Get a Quote |
| STXBP1 Knockout HeLa Cell Line | EDJ-KQ28084 | Human | 6812 | Details Get a Quote |
| STXBP1 Knockout A-549 Cell Line | EDJ-KQ29351 | Human | 6812 | Details Get a Quote |
| STXBP1 Knockout HCT 116 Cell Line | EDJ-KQ29352 | Human | 6812 | Details Get a Quote |
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