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Symbol XBP1 contributors: mct - updated : 06-09-2017
HGNC name X-box binding protein 1
HGNC id 12801
TYPE functioning gene
STRUCTURE 6.01 kb     4 Exon(s)
10 Kb 5' upstream gene genomic sequence study
text structure a cis-acting element in the MDG1/ERdj4 promoter region
MAPPING cloned Y linked N status confirmed
TRANSCRIPTS type messenger
identificationnb exonstypebpproduct
ProteinkDaAAspecific expressionYearPubmed
5 - 1820 29 261 - 2011 21398633
  • also called XBP1(U), having a hydrophobic region 2 (HR2), which is a membrane-targeting signal, and present only on the XBP1U protein, and a C-terminus responsible for the translational pausing and required for the efficient targeting and splicing of the XBP1u mRNA
  • spliced form acting as a transcription factor and inducing the expression of ER-resident molecular chaperones
  • in the cytosol is an unspliced precursor form of XBP1s, under unstressed conditions
  • upon ER stress, cleaved to initiate the unconventional splicing of XBP1u mRNA on the ER membrane
  • acts as a dominant negative of spliced XBP1
  • 6 splicing 1810 56 376 - 2011 21398633
  • also called XBP1(S)
  • key factor in ER stress, through transcriptionnal regulation of an array of genes, including molecular chaperones
  • upon endoplasmic reticulum (ER) stress, mammalian cells induce the synthesis of a transcriptional activator XBP1s to alleviate the stress
  • phosphate was incorporated into XBP1s mRNA in the cytosol to ligate the two exons
  • active/spliced form of XBP1 protein, that directly binds to the AABS (A-activator-binding site) in the iNOS promoter
  • induces autophagic response in endothelial cells
    Type ubiquitous
       expressed in (based on citations)
    SystemOrgan level 1Organ level 2Organ level 3Organ level 4LevelPubmedSpeciesStageRna symbol
    Digestiveliver   highly
    Endocrineplacenta   highly
    Reproductivefemale systembreastmammary gland highly
     female systemuterus  highly
     female systemplacenta  highly
    cell lineage
    cell lines highly in hepatocellular carcinomas
    at STAGE
    physiological period pregnancy
    Text placenta
  • basic leucine zipper (bZIP) motif
    interspecies homolog to murine Xbp1
  • CREB/ATF family
  • bZIP family
  • CATEGORY immunity/defense , DNA associated , transcription factor
    SUBCELLULAR LOCALIZATION     intracellular
    intracellular,cytoplasm,organelle,endoplasmic reticulum
  • spliced XBP1 translocates into the nucleus and binds as homodimer or heterodimer to the BECN1 gene promoter, leading to BECN1 transcription
  • basic FUNCTION
  • acting as an essential survival factor for hypoxic stress and tumor growth
  • key transcription factor in the endoplasmic reticulum (ER) stress response pathway
  • plays an important role in membrane lipid synthesis in the ER
  • transcription factor governing hepatic lipogenesis
  • key regulator of the unfolded protein response, required for the unrelated function of normal fatty acid synthesis in the liver
  • under endoplasmic reticulum (ER) stress conditions, is processed by unconventional splicing and translated into a functional transcription factor
  • required for development and maintenance of secretory cells and linked to JNK activation
  • transcription factor essential for hepatocyte growth, as well as for plasma cell differentiation
  • key effector of the unfolded protein response (UPR), in skeletal muscle and secretory cells
  • regulates functionally distinct targets through different sequence motifs
  • may regulate signal transduction, transcription factors and bone marrow colonization in B cells
  • major endoplasmic reticulum stress-linked transcriptional factor, contributing to cellular resistance to oxidative stress
  • having a protective role against oxidative stress, and its positive regulation of catalase expression may at least in part account for this function
  • essential for survival under hypoxic conditions, and positively regulates tumor growth
  • key UPR transcription factor that regulates genes involved in protein folding and quality control
  • having a function in the control of autophagy and indicate critical cross-talk between these two signaling pathways that can provide protection against neurodegeneration
  • key modulator of the UPR (unfolded protein response), which is involved in a wide range of pathological and physiological processes
  • involved in the regulation of NOS2 induction by the interaction between its spliced and unspliced forms in response to ER stress
  • first identified as a key regulator of major histocompatibility complex (MHC) class II gene expression in B cells
  • critical for cell fate determination in response to ER stress
  • role for XBP1 in an antiviral response
  • the transcription factor XBP1 activates genes in protein secretory pathways and is required for the development of certain secretory cells
  • involvement of XBP1 in huntington pathogenesis probably due to an ER stress-independent mechanism involving the control of FOXO1 and autophagy levels
  • unexpected role of XBP1 in controlling a dynamic crosstalk with the FOXO1 and the autophagy pathway to modulate HD pathogenesis
  • acetylation status of the ER is regulated by ERN1/XBP1, which acts by controlling the influx of acetyl-CoA through the membrane transporter SLC33A1
  • could be used as an important pharmacological target that can regulate the autophagic machinery and endothelial cell death
  • may control the transcriptional activation of BECN1 through recruiting other co-factors that induce acetylation and protein stability and/or inhibit deacetylation in a cell-dependent manner
  • XBP1 represents a key component of the endoplasmatic reticulum (ER) stress response and is required for the production of several pro-inflammatory cytokines
  • CELLULAR PROCESS nucleotide, transcription
    ERN1-XBP1 pathway is involved in osteoblast differentiation through promoting SP7 transcription
    a component
  • key component of the endoplasmic reticulum (ER) stress response
    DNA binding to HLA-DRA, HLA-DRB promoter
    small molecule
  • regulating DNAJB9, a member of the DnaJ family (target sequence for the IRE1-XBP1 pathway under ER stress conditions)
  • interacting with BHLHA15, a critical regulator of differentiation (important target of XBP1, providing an explanation for developmental defects associated with XBP1 loss of function)
  • SUMOylated, mainly by PIAS2 at two lysine residues located in the C-terminal transactivation domain
  • target of acetylation and deacetylation mediated by EP300 and SIRT1 (sirtuin 1) respectively (
  • interacts with the Forkhead box O1 (FOXO1A) transcription factor and directs it toward proteasome-mediated degradation (through its interaction with FoxO1, can bypass hepatic insulin resistance independent of its effects on ER folding capacity)
  • IL3 interacting with XBP1 (the proper transcriptional and splicing regulation of XBP1 by IL3 signaling is important in homeostasis of hematopoietic cells)
  • ERN1 target XBP1, and are essential for bone morphogenic protein 2-induced osteoblast differentiation
  • TMTC3 is involved in the endoplasmic reticulum stress response, by modulating proteasome activity and XBP1 transcript expression
  • spliced XBP1 serves as an important effector of ERN1, activating its target genes
  • TBC1D23 likely acts downstream of the TLR-signaling adaptors MYD88 and TICAM2 and upstream of the transcription factor XBP1
  • ERN1/XBP1 controls the induction of autophagy by activating the expression of the ER membrane transporter SLC33A1, which ensures continuous supply of acetyl-CoA into the lumen of the ER
  • BMP2 is known to activate unfolded protein response signaling molecules, including XBP1 and ATF6
  • XBP1 associates with RUNX2 and enhances RUNX2-induced chondrocyte hypertrophy
  • may be a novel regulator of hypertrophic chondrocyte differentiation by acting as a cofactor of RUNX2 and affecting IHH/PTHRP signaling
  • ELL2 is important for many aspects of Ab secretion, XBP1 expression, and the unfolded protein response (UPR) (
  • acute METTL14 deficiency in beta-cells induces glucose intolerance by increasing the ERN1/XBP1 pathway
  • signaling via TLR7 leads to an upregulation of XBP1 and IFNA1-production
  • central role of XBP1 in TLR7-induced IFNA1 production
  • cell & other
    activated by IRE1
    induced by ATF6
    Other regulated by alpha FP
    activated in B cells when they differentiate to plasma cells
    corresponding disease(s)
    Other morbid association(s)
    TypeGene ModificationChromosome rearrangementProtein expressionProtein Function
    tumoral       loss of function
    in prostate cancer in progression
    tumoral     --over  
    in primary colorectal carcinomas and in colorectal adenomas
    constitutional     --over  
    increased XBP1 expression may contribute to a reduction of oxidative stress and prevention of aging
    constitutional     --low  
    led to augmented expression of FOXO1, a key transcription factor regulating autophagy in neurons
  • to bipolar disorder
  • to inflammatory bowel disease
  • Variant & Polymorphism other
  • C116G increases the risk of bipolar disorder
  • variants increasing the risk of inflammatory bowel disease
  • Candidate gene
    Therapy target
    potential of XBP1 as targets for Alzheimer disease therapeutics
    diabetetype 2 
    potential new therapeutic approach for the treatment of type 2 diabetes
    is a potential novel therapeutic target in IFNA1-driven autoimmune and inflammatory diseases
  • mutant SOD1 transgenic mice with specific deletion of XBP-1 in the nervous system were more resistant to developing disease, correlating with increased levels of autophagy in motoneurons and reduced accumulation of mutant SOD1 aggregates in the spinal cord
  • Xbp1-deficient mice were more resistant to developing disease features, associated with improved neuronal survival and motor performance, and a drastic decrease in mHtt levels