| 2001 |
XBP1 mRNA is a substrate of the IRE1 endoribonuclease in mammals; IRE1 performs unconventional cytoplasmic splicing of XBP1 mRNA under ER stress, producing a frameshift that generates a highly active transcription factor (spliced XBP1). Additionally, ATF6 induces transcription of XBP1 mRNA upstream of this splicing event. |
Molecular cloning, reporter assays, mRNA splicing analysis, and functional UPR activation assays in mammalian cells |
Cell |
High |
11779464
|
| 2003 |
IRE1-mediated splicing of XBP1 is required for plasma cell differentiation and immunoglobulin production; only spliced XBP1 rescues immunoglobulin production in XBP1-/- B cells. IL-4 signaling controls XBP1 transcription during B cell differentiation, while immunoglobulin synthesis drives post-transcriptional XBP1 processing. XBP1 also controls IL-6 production, which is essential for plasma cell survival. |
Genetic rescue experiments in XBP1-/- mouse B cells, B cell differentiation assays, cytokine measurements |
Nature immunology |
High |
12612580
|
| 2004 |
Hypoxia induces XBP1 at the transcriptional level and activates splicing of its mRNA, resulting in increased activated XBP1 protein. XBP1-deficient cells show increased apoptosis and decreased clonogenic survival under hypoxia, establishing XBP1 as an essential survival factor for hypoxic stress. |
Gene expression analysis, XBP1-deficient cell lines, clonogenic survival assays, apoptosis assays, tumor xenograft models |
Cancer research |
High |
15342372
|
| 2004 |
Hepatitis C virus suppresses the IRE1-XBP1 pathway; HCV replicons elevate XBP1 expression but repress its trans-activating activity, preventing XBP1-dependent induction of EDEM (required for misfolded protein degradation). IRE1α-null MEFs with defective IRE1-XBP1 signaling show elevated HCV IRES-mediated translation. |
HCV replicon cell lines, XBP1 trans-activation assays, IRE1α-null MEFs, EDEM expression analysis |
The Journal of biological chemistry |
Medium |
14960590
|
| 2007 |
Genome-wide mapping revealed that XBP1 regulates distinct target genes in different cell types through different sequence motifs; it controls a core ER-maintenance gene set in all cell types plus tissue-specific targets. XBP1 was found to directly regulate Mist1, a critical regulator of differentiation, explaining developmental defects in XBP1-null mice. |
Genome-wide ChIP, microarray expression profiling in skeletal muscle and secretory cells |
Molecular cell |
High |
17612490
|
| 2009 |
The IRE1α-XBP1 pathway is indispensable for adipogenesis; C/EBPβ directly binds the Xbp1 proximal promoter to induce its expression, and XBP1 then binds the Cebpa promoter to activate C/EBPα expression. Only the IRE1α-spliced form of XBP1 (XBP1s) rescues adipogenic defects in XBP1-deficient cells. |
XBP1-deficient MEFs, 3T3-L1 knockdown, promoter ChIP assays, adipogenic differentiation assays, XBP1s rescue experiments |
Cell metabolism |
High |
19490910
|
| 2009 |
XBP1 is required for de novo fatty acid synthesis in the liver; XBP1 protein expression is induced by high-carbohydrate diet and directly controls induction of genes involved in fatty acid synthesis. Liver-specific XBP1 deletion results in profound hypocholesterolemia and hypotriglyceridemia due to diminished hepatic lipid production. |
Inducible liver-specific XBP1 knockout mice, gene expression analysis, lipid measurements |
Annals of the New York Academy of Sciences |
High |
19751410
|
| 2012 |
miR-30c-2* (miR-30c-2-3p) is induced by the PERK pathway of the UPR and directly suppresses XBP1 expression, limiting the scale of XBP1-mediated gene expression and influencing cell fate in the UPR. This represents a cross-talk mechanism where PERK signaling dampens IRE1/XBP1 output. |
miRNA induction assays, miRNA overexpression/inhibition, XBP1 protein/mRNA measurement, PERK pathway genetic approaches |
The Journal of cell biology |
Medium |
22431749
|
| 2014 |
XBP1 promotes TNBC tumorigenicity by assembling a transcriptional complex with HIF1α that recruits RNA polymerase II to regulate HIF1α target gene expression. Genome-wide mapping of the XBP1 transcriptional regulatory network confirmed physical interaction of XBP1 with HIF1α. |
Genome-wide ChIP-seq, Co-immunoprecipitation, XBP1 depletion (shRNA), tumor xenograft models |
Nature |
High |
24670641
|
| 2014 |
XBP1 regulates epithelial-to-mesenchymal transition (EMT) in breast cancer by upregulating the key EMT regulator Snail, leading to decreased E-cadherin and increased mesenchymal marker expression. XBP1 knockdown restores E-cadherin expression and suppresses cell invasion. |
siRNA knockdown, XBP1 overexpression, E-cadherin/mesenchymal marker expression assays, invasion assays |
Cellular signalling |
Medium |
25280941
|
| 2015 |
Constitutive XBP1 activation in tumor-associated dendritic cells, fueled by lipid peroxidation byproducts, induces a triglyceride biosynthetic program leading to abnormal lipid accumulation and inhibition of anti-tumor T cell support. DC-specific XBP1 deletion or nanoparticle-mediated XBP1 silencing in tDCs restored immunostimulatory activity. |
DC-specific XBP1 conditional knockout mice, nanoparticle-mediated XBP1 silencing, lipid accumulation assays, T cell activation assays, tumor progression models |
Cell |
High |
26073941
|
| 2015 |
XBP1 directly binds the promoter of NFATc1 and induces its transcription to drive osteoclastogenesis. IRE1α activation during osteoclastogenesis is partially dependent on Ca2+ oscillation via ITPR2 and ITPR3 in the ER. |
Conditional IRE1α knockout mice, osteoclast differentiation assays, ChIP for XBP1 binding to NFATc1 promoter, pharmacological inhibition of ITPR2/3 |
The Journal of clinical investigation |
High |
26193638
|
| 2015 |
SEC63 deficiency selectively activates IRE1α-XBP1 in the ER; SEC63 exists in a complex with PC1 (polycystin-1). XBP1 is required for GPS cleavage and maturation of PC1; enforced XBP1s expression enhances GPS cleavage of PC1 and ameliorates polycystic disease. |
Murine genetic models (SEC63/XBP1 double knockout), co-immunoprecipitation, GPS cleavage assays, XBP1s overexpression |
The Journal of clinical investigation |
High |
25844898
|
| 2015 |
Hepatic XBP1 controls the adaptive UPR response in the liver; liver-specific Xbp1 knockout mice cannot resolve ER stress, leading to sustained UPR activation, progressive liver injury, apoptosis, and fibrosis in response to pharmacological ER stress. |
Liver-specific Xbp1 knockout mice, pharmacological ER stress induction, liver injury/apoptosis/fibrosis assessment |
The Journal of biological chemistry |
High |
26504083
|
| 2016 |
In addition to ATF6-mediated transcriptional induction of XBP1 mRNA, IRE1α expression is induced by ATF4 downstream of PERK under ER stress; increased IRE1α expression raises the XBP1 mRNA splicing ratio, amplifying and prolonging IRE1α-XBP1 pathway activation. |
IRE1α/ATF4 knockdown, XBP1 splicing ratio measurement, ER stress time-course experiments |
Scientific reports |
Medium |
27052593
|
| 2017 |
Unspliced XBP1 (XBP1-u) negatively regulates the p53/p21 axis by binding and stabilizing MDM2 protein, inhibiting MDM2 self-ubiquitination and thereby enhancing p53 ubiquitination and degradation. The C-terminal domain of XBP1-u (which differs from XBP1-s due to a codon shift) mediates MDM2 binding. |
shRNA library screen, Co-immunoprecipitation, ubiquitination assays, domain mapping, cell cycle analysis |
Science advances |
High |
29057323
|
| 2017 |
XBP1s directly binds the Cyclin D1 promoter to activate its expression, mediating IRE1α-dependent cell proliferation in colorectal cancer cells. |
ChIP, luciferase reporter assays, siRNA knockdown of IRE1α/XBP1, proliferation assays |
Biochemical and biophysical research communications |
Medium |
26742428
|
| 2017 |
XBP1s binds the IL-6 promoter directly and activates its expression in melanoma cells; secreted IL-6 then activates JAK/STAT3 signaling in an autocrine/paracrine manner to promote melanoma cell proliferation. Inhibition of IRE1α RNase activity abolishes this effect. |
ChIP experiments, luciferase reporter assays, XBP1s ectopic expression, IRE1α inhibition, western blotting for STAT3 |
Journal of translational medicine |
Medium |
28222747
|
| 2018 |
IRE1α-XBP1 activation in T cells suppresses mitochondrial activity and IFNγ production in ovarian cancer. Mechanistically, XBP1 induction regulates the abundance of glutamine carriers, limiting glutamine influx needed for mitochondrial respiration under glucose-deprived conditions. XBP1-deficient T cells show improved effector capacity. |
T cell-specific XBP1 deletion, metabolic assays, glutamine transporter expression analysis, mitochondrial respiration measurement, mouse tumor models |
Nature |
High |
30305738
|
| 2018 |
MYC directly controls IRE1 transcription by binding to its promoter and enhancer. Furthermore, MYC forms a transcriptional complex with XBP1 and enhances XBP1 transcriptional activity. XBP1 is a synthetic lethal partner of MYC in breast cancer. |
ChIP for MYC binding to IRE1 promoter/enhancer, Co-immunoprecipitation of MYC-XBP1 complex, XBP1 silencing in MYC-hyperactivated cells, PDX mouse models |
The Journal of clinical investigation |
High |
29480818
|
| 2018 |
IRE1α-XBP1 constitutive activation in pancreatic β cells regulates oxidative folding of proinsulin by controlling expression of five protein disulfide isomerases (PDI, PDIR, P5, ERp44, ERp46). Reconstitution of the IRE1α-XBP1 pathway in Ire1α-deleted insulinoma cells restored proinsulin content, insulin secretion, and PDI expression. |
β cell-specific Ire1α conditional knockout mice, Cre-loxP cell lines, insulin secretion assays, PDI expression analysis, IRE1α-XBP1 reconstitution |
The Journal of cell biology |
High |
29507125
|
| 2018 |
XBP1s directly transactivates the human PTGS2 (COX-2) and PTGES genes to enable optimal prostaglandin E2 production in myeloid cells. IRE1α-XBP1-deficient myeloid cells show compromised induction of Cox-2 and mPGES-1 under ER stress or pattern recognition receptor stimulation. |
IRE1α-deficient myeloid cells, XBP1-deficient myeloid cells, ChIP/transactivation assays for PTGS2/PTGES promoters, PGE2 measurements, pain behavior models |
Science |
High |
31320508
|
| 2018 |
2',3'-cyclic nucleotide phosphodiesterase (CNP) suppresses RtcB-mediated XBP1 splicing by hydrolyzing 2',3'-cyclic phosphate on cleaved XBP1 exon termini; conversely, RNA 3'-terminal cyclase (RtcA) facilitates XBP1 splicing by converting 2'-phosphate back to 2',3'-cyclic phosphate for RtcB ligation. |
In vitro splicing assays, mammalian cell lines, CNP/RtcA overexpression/knockdown, XBP1 splicing measurement |
The Journal of biological chemistry |
High |
30355738
|
| 2019 |
Muscle-specific deletion of XBP1 ameliorates cancer cachexia-induced skeletal muscle wasting; overexpression of active XBP1 causes myotube atrophy. XBP1 acts downstream of TLR/MyD88 signaling to mediate muscle wasting, identifying a TLR/MyD88/XBP1 axis in cancer cachexia. |
Muscle-specific XBP1 conditional knockout mice, Lewis lung carcinoma tumor-bearing model, myotube atrophy assays, XBP1 overexpression |
Molecular and cellular biology |
High |
31138662
|
| 2019 |
Constitutive XBP-1s expression in C. elegans increases lysosomal lipase activity and upregulates transcription of Δ9 desaturase FAT-6, increasing oleic acid levels; FAT-6 is required for the full lifespan extension induced by XBP-1s. |
C. elegans transgenic expression, metabolomics, fat-6 genetic epistasis, lysosomal lipase activity assays |
Cell reports |
Medium |
31315038
|
| 2020 |
Insulin-activated kinase AKT directly phosphorylates IRE1 at S724, which mediates XBP1u mRNA splicing to generate XBP1s in mouse liver in the fed state, stimulating lipogenic gene expression. In the fasted state, XBP1u (not XBP1s) increases cAMP-stimulated gluconeogenic gene expression (G6pc, Pck1) and glucose production. |
AKT phosphorylation site mapping, in vitro kinase assays, hepatocyte-specific XBP1 depletion with re-expression, gluconeogenesis/lipogenesis assays, primary hepatocytes |
The Journal of biological chemistry |
High |
35863429
|
| 2020 |
Hepatocyte-specific XBP1 deletion sensitizes mice to liver injury through hyperactivation of IRE1α (evidenced by XBP1 mRNA splicing, JNK activation, and RIDD). Concomitant deletion of both XBP1 and IRE1α protected mice from fructose-mediated liver injury, demonstrating that deleterious effects of XBP1 deletion are primarily due to IRE1α hyperactivation. |
Hepatocyte-specific single and double (XBP1/IRE1α) conditional knockout mice, dietary challenge, liver injury markers, IRE1α activity assays |
Cell death and differentiation |
High |
33219328
|
| 2020 |
Liver-specific ablation of XBP1 disrupts the hepatic 12-hour clock and promotes NAFLD; XBP1s directly binds to the hepatic 12-hour cistrome. XBP1 ablation reduces membrane fluidity and impairs lipid homeostasis via fatty acid monounsaturation and phospholipid remodeling pathways. |
Liver-specific XBP1 knockout mice, ChIP-seq of 12-hour cistrome, genome-wide transcriptional profiling, lipid/membrane fluidity assays |
Nature communications |
High |
33277471
|
| 2021 |
Unspliced XBP1 (XBP1u) directly binds β-catenin via amino acids 205–230 in its C-terminal degradation domain, promoting β-catenin ubiquitin-proteasomal degradation independently of the GSK-3β destruction complex, thereby inhibiting β-catenin/TCF-mediated transcription of Runx2 and Msx2 and suppressing vascular calcification. |
Interactome analysis, Co-immunoprecipitation, ubiquitination assays, domain mapping, smooth muscle cell-specific XBP1 knockout mice, vascular calcification models |
Circulation research |
High |
34870453
|
| 2021 |
XBP1s directly binds the TAp73 promoter and suppresses its transcriptional activity, reducing p53-family tumor suppression and promoting colorectal cancer cell proliferation. TAp73 overexpression cancelled the pro-proliferative effect of XBP1s. |
ChIP for XBP1s binding to TAp73 promoter, luciferase reporter assays, XBP1s overexpression, TAp73 rescue experiments |
Biochemical and biophysical research communications |
Medium |
30473215
|
| 2021 |
XBP1s genome-wide mRNA profiling identified XBP1 as a transcriptional repressor of PUMA (proapoptotic gene) and IRE1 mRNA expression during UPR, providing a negative feedback mechanism. Elevated XBP1 expression during ER stress had a prosurvival effect with reduced PUMA protein. |
XBP1s-inducible human cell line, siRNA silencing, next-generation RNA sequencing, bioinformatic analysis of XBP1-binding motifs |
Cellular and molecular life sciences |
Medium |
34636989
|
| 2022 |
Unspliced XBP1 (XBP1-u) colocalizes with SREBP2 and inhibits its ubiquitination/proteasomal degradation, stabilizing SREBP2 and activating HMGCR transcription, thereby promoting cholesterol biosynthesis and tumorigenesis in hepatocellular carcinoma. |
Co-immunoprecipitation, ubiquitination assays, SREBP2 stability assays, HMGCR expression analysis, tumor growth experiments |
Cellular and molecular life sciences |
Medium |
35933495
|
| 2022 |
Spliced XBP1 binds directly to the BNIP3 promoter and inhibits BNIP3 transcription in macrophages, thereby suppressing BNIP3-mediated mitophagy. Reduced mitophagy in Xbp1-expressing macrophages promotes cytosolic mtDNA leakage, activating cGAS/STING/NLRP3 signaling to drive liver fibrosis. |
Chromatin immunoprecipitation (ChIP) for XBP1 binding to Bnip3 promoter, RNA sequencing, myeloid-specific Xbp1 knockout mice, BNIP3 knockdown, liver fibrosis models |
JHEP reports |
High |
36185574
|
| 2022 |
Cancer cell XBP1 favors synthesis and secretion of cholesterol in small extracellular vesicles; cholesterol is internalized by MDSCs via macropinocytosis, activating MDSCs and causing immunosuppression. XBP1 genetic or pharmacological depletion reduces MDSC abundance and triggers anti-tumor responses. |
XBP1 genetic depletion/pharmacological inhibition, extracellular vesicle isolation, cholesterol quantification, MDSC activation assays, tumor models |
Cell metabolism |
Medium |
36351432
|
| 2022 |
Spliced XBP1 enhances the activity of the NLRP3 promoter (demonstrated by luciferase reporter assay), linking XBP1-mediated ER-mitochondria crosstalk to caspase-1-dependent inflammation in renal ischemia/reperfusion injury. |
Luciferase reporter assay for NLRP3 promoter, XBP1 interference in renal tubular cells, in vivo renal IRI model |
Cell death discovery |
Medium |
36801911
|
| 2022 |
In Drosophila, IRE1-mediated phosphorylation of the RNA-binding protein Pumilio enables Pumilio to protect spliced Xbp1 mRNA from regulated Ire1-dependent decay (RIDD). hIRE1 can directly phosphorylate Pumilio, and phosphorylated Pumilio binds and stabilizes Xbp1spliced mRNA. |
Drosophila genetics, in vitro IRE1 kinase assays, mRNA stability assays, Pumilio binding site identification in Xbp1 3'UTR |
Nature communications |
High |
35332141
|
| 2022 |
ATF6α is required for full activation of XBP1 target genes in pancreatic islet cells; acute ATF6α knockdown reduces induction of XBP1 targets without altering XBP1 mRNA splicing dynamics. XBP1 is not required for activation of ATF6α targets, establishing ATF6α as upstream of XBP1 target expression but not of XBP1 splicing. |
Acute ATF6α conditional knockdown in primary mouse islets (adenovirus-Cre), timed ER stressor exposures, transcriptional target gene measurement |
The Journal of biological chemistry |
Medium |
32788214
|
| 2023 |
XBP1 overexpression increases Hrd1 expression; Hrd1 then interacts with and ubiquitinates Nrf2 under high-glucose conditions (confirmed by Co-IP and ubiquitylation assays), promoting ferroptosis via the XBP1-Hrd1-Nrf2 pathway in diabetic nephropathy. |
Co-immunoprecipitation, ubiquitylation assays, XBP1 overexpression, ferroptosis markers, high-glucose cell model |
Biomedicine & pharmacotherapy |
Medium |
37224754
|
| 2023 |
XBP1 inhibits SLC38A2 (glutamine transporter) expression by directly binding to its promoter; reduced SLC38A2 decreases glutamine uptake and causes immune dysfunction in cytotoxic T cells in multiple myeloma. |
Single-cell RNA sequencing, in vitro XBP1 overexpression/inhibition, ChIP for XBP1 binding to SLC38A2 promoter, glutamine uptake assays, T cell functional assays |
Cancer letters |
Medium |
37054944
|
| 2023 |
XBP1 in dendritic cells directly promotes TIM4 mRNA and protein expression in response to IL-2. RhoA facilitates binding between XBP1 and GATA3 in CD4+ T cells; XBP1 induces GATA3 phosphorylation to promote Il4 gene transcription and Th2 polarization. |
Xbp1-deficient CD4+ T cells and DCs, XBP1-TIM4 promoter binding assays, Co-IP for XBP1-GATA3 interaction, GATA3 phosphorylation assays, in vivo airway allergy models |
Science signaling / Theranostics |
Medium |
35910793 37368951
|
| 2024 |
XBP1 upregulation promotes ferritinophagy via NCOA4; SeNPs protect against ferroptosis by upregulating XBP1, which in turn suppresses NCOA4-mediated ferritinophagy. XBP1 downregulation promoted ferritinophagy and partially counteracted protective effects on ferroptosis. |
In vitro H/R model, in vivo I/R-AKI mouse model, XBP1 knockdown, ferritinophagy and ferroptosis markers, lysosomal Fe2+ measurement |
Cell communication and signaling |
Low |
39061070
|