Rabbit XBP1 Polyclonal Antibody | anti-XBP1 antibody

Phospho-XBP1 (Ser68) Antibody

Cat. Num. AAA9612780

• Gene Names: XBP1; XBP2; TREB5; XBP-1
• Reactivity: Human, Mouse, Rat
• Applications: Immunofluorescence, Immunocytochemistry, ELISA
• Purity: The antibody is from purified rabbit serum by affinity purification via sequential chromatography on phospho-peptide and non-phospho-peptide affinity columns.
• Synonyms: XBP1; Polyclonal Antibody; Phospho-XBP1 (Ser68) Antibody; Tax responsive element binding protein 5; Tax-responsive element-binding protein 5; TREB5; X box binding protein 1; X box binding protein 2; X-box-binding protein 1; XBP 1; XBP-1; XBP1_HUMAN; XBP2; anti-XBP1 antibody

• Host: Rabbit
• Reactivity: Human, Mouse, Rat
• Clonality: Polyclonal
• Isotype: Rabbit IgG
• Specificity: Phospho-XBP1 (Ser68) Antibody detects endogenous levels of XBP1 only when phosphorylated at Ser68.; Tissue Specificity: Expressed in plasma cells in rheumatoid synovium. Over-expressed in primary breast cancer and metastatic breast cancer cells. Isoform 1 and isoform 2 are expressed at higher level in proliferating as compared to confluent quiescent endothelial cells.
• Purity/Purification: The antibody is from purified rabbit serum by affinity purification via sequential chromatography on phospho-peptide and non-phospho-peptide affinity columns.
• Form/Format: Liquid. Rabbit IgG in phosphate buffered saline, pH7.4, 150mM NaCl, 0.02% sodium azide and 50% glycerol.
• Concentration: 1mg/ml (varies by lot)

• Applicable Applications for anti-XBP1 antibody: Immunofluorescence (IF), Immunocytochemistry (ICC), Peptide ELISA (EIA)
• Application Notes: IF/ICC: 1:100-1:500; Peptide ELISA: 1:20,000-1:40,000
• Immunogen: A synthesized peptide derived from human XBP1 around the phosphorylation site of Ser68.
• Conjugation: Unconjugated
• Fragment: Fab fragment
• Post Translational Modifications: Isoform 2 is acetylated by EP300; acetylation positively regulates the transcriptional activity of XBP1 isoform 2. Isoform 2 is deacetylated by SIRT1; deacetylation negatively regulates the transcriptional activity of XBP1 isoform 2.Isoform 1 is ubiquitinated, leading to proteasome-mediated degradation in response to ER stress.X-box-binding protein 1, cytoplasmic form and luminal form are produced by intramembrane proteolytic cleavage of ER membrane-anchored isoform 1 triggered by HM13/SPP in a DERL1-RNF139-dependent and VCP/p97-independent manner. X-box-binding protein 1, luminal form is ubiquitinated leading to proteasomal degradation.
• Subunit Structure: Isoform 2 interacts with SIRT1. Isoform 2 interacts with PIK3R1 and PIK3R2; the interactions are direct and induce translocation of XBP1 isoform 2 into the nucleus and the unfolded protein response (UPR) XBP1-dependent target genes activation in a ER stress- and/or insulin-dependent but PI3K-independent manner. Isoform 2 interacts with FOXO1; the interaction is direct and leads to FOXO1 ubiquitination and degradation via the proteasome pathway in hepatocytes (By similarity). Isoform 1 interacts with HM13. Isoform 1 interacts with RNF139; the interaction induces ubiquitination and degradation of isoform 1. Isoform 1 interacts (via luminal domain) with DERL1; the interaction obviates the need for ectodomain shedding prior HM13/SPP-mediated XBP1 isoform 1 cleavage. Isoform 1 interacts with isoform 2; the interaction sequesters isoform 2 from the nucleus and enhances isoform 2 degradation in the cytoplasm. Isoform 1 interacts with HDAC3 and AKT1; the interactions occur in endothelial cell (EC) under disturbed flow. Isoform 1 interacts with the oncoprotein FOS. Isoform 2 interacts with ATF6; the interaction occurs in a ER stress-dependent manner and is required for DNA binding to the unfolded protein response element (UPRE). Isoform 2 interacts with PIK3R1; the interaction is direct and induces translocation of XBP1 isoform 2 into the nucleus and the unfolded protein response (UPR) XBP1-dependent target genes activation in a ER stress- and/or insulin-dependent but PI3K-independent manner.
• Similarity: Isoform 1 and isoform 2 N-terminus domains are necessary for nuclear localization targeting. Isoform 1 C-terminus domain confers localization to the cytoplasm and is sufficient to impose rapid degradation (By similarity). Isoform 1 transmembrane signal-anchor domain is necessary for its own mRNA to be recruited to the endoplasmic reticulum (ER) which will undergo unconventional ERN1-dependent splicing in response to ER stress (PubMed:19394296, PubMed:21233347). Isoform 1 N-terminus and C-terminus regions are necessary for DNA-binding and weak transcriptional activity, respectively. Isoform 2 N-terminus and C-terminus regions are necessary for DNA-binding and strong transcriptional activity upon ER stress, respectively (PubMed:11779464, PubMed:8657566). Isoform 2 C-terminus region contains a nuclear exclusion signal (NES) at positions 186 through 208. Isoform 2 C-terminus region contains a degradation domain at positions 209 through 261 (PubMed:16461360).Belongs to the bZIP family.
• Subcellular Location: Endoplasmic reticulum.; Note: Colocalizes with ERN1 andKDR in the endoplasmic reticulum in endothelial cells in a vascular endothelial growth factor (VEGF)-dependent manner (PubMed:23529610).Nucleus. Cytoplasm. Endoplasmic reticulum membrane>Single-pass type II membrane protein. Endoplasmic reticulum membrane>Peripheral membrane protein. Membrane>Peripheral membrane protein.; Note: Shows no preferential localization to either the nucleus or the cytoplasm (By similarity). Shuttles between the nucleus and the cytoplasm in a CRM1-dependent manner (PubMed:16461360). Localizes predominantly at the endoplasmic reticulum membrane as a membrane-spanning protein; whereas may be only marginally localized on the cytosolic side of the ER membrane as a peripheral membrane (PubMed:19394296, PubMed:25190803).Nucleus. Cytoplasm.; Note: Localizes predominantly in the nucleus. Colocalizes in the nucleus with SIRT1. Translocates into the nucleus in a PIK3R-, ER stress-induced- and/or insulin-dependent manner (By similarity).Cytoplasm. Nucleus.; Note: Localizes in the cytoplasm and nucleus after HM13/SPP-mediated intramembranaire proteolytic cleavage of isoform 1 (PubMed:25239945).
• Preparation and Storage: Store at -20 degree C. Stable for 12 months from date of receipt.

Immunofluorescence (IF)/Immunocytochemistry (ICC)

(Staining Hela cells(heat shock treatment) by IF/ICC. The samples were fixed with PFA and permeabilized in 0.1% Triton X-100,then blocked in 10% serum for 45 minutes at 25 degree C. Samples were then incubated with primary Ab(AF3712) and mouse anti-beta tubulin Ab(T0023) for 1 hour at 37 degree C. An AlexaFluor594 conjugated goat anti-rabbit IgG(H+L) Ab(Red) and an AlexaFluor488 conjugated goat anti-mouse IgG(H+L) Ab(Green) were used as the secondary antibody.The nuclear counter stain is DAPI (blue).)

Related Product Information for anti-XBP1 antibody

Functions as a transcription factor during endoplasmic reticulum (ER) stress by regulating the unfolded protein response (UPR). Required for cardiac myogenesis and hepatogenesis during embryonic development, and the development of secretory tissues such as exocrine pancreas and salivary gland (By similarity). Involved in terminal differentiation of B lymphocytes to plasma cells and production of immunoglobulins. Modulates the cellular response to ER stress in a PIK3R-dependent manner. Binds to the cis-acting X box present in the promoter regions of major histocompatibility complex class II genes. Involved in VEGF-induced endothelial cell (EC) proliferation and retinal blood vessel formation during embryonic development but also for angiogenesis in adult tissues under ischemic conditions. Functions also as a major regulator of the UPR in obesity-induced insulin resistance and type 2 diabetes for the management of obesity and diabetes prevention (By similarity).Plays a role in the unconventional cytoplasmic splicing processing of its own mRNA triggered by the endoplasmic reticulum (ER) transmembrane endoribonuclease ENR1: upon ER stress, the emerging XBP1 polypeptide chain, as part of a mRNA-ribosome-nascent chain (R-RNC) complex, cotranslationally recruits its own unprocessed mRNA through transient docking to the ER membrane and translational pausing, therefore facilitating efficient IRE1-mediated XBP1 mRNA isoform 2 production. In endothelial cells (EC), associated withKDR, promotes IRE1-mediated XBP1 mRNA isoform 2 productions in a vascular endothelial growth factor (VEGF)-dependent manner, leading to EC proliferation and angiogenesis. Functions as a negative feed-back regulator of the potent transcription factor XBP1 isoform 2 protein levels through proteasome-mediated degradation, thus preventing the constitutive activation of the ER stress response signaling pathway. Inhibits the transactivation activity of XBP1 isoform 2 in myeloma cells (By similarity). Acts as a weak transcriptional factor. Together with HDAC3, contributes to the activation of NFE2L2-mediated HMOX1 transcription factor gene expression in a PI (3)K/mTORC2/Akt-dependent signaling pathway leading to EC survival under disturbed flow/oxidative stress. Binds to the ER stress response element (ERSE) upon ER stress. Binds to the consensus 5'-GATGACGTG[TG]N (3)[AT]T-3' sequence related to cAMP responsive element (CRE)-like sequences. Binds the Tax-responsive element (TRE) present in the long terminal repeat (LTR) of T-cell leukemia virus type 1 (HTLV-I) and to the TPA response elements (TRE). Associates preferentially to the HDAC3 gene promoter region in a static flow-dependent manner. Binds to the CDH5/VE-cadherin gene promoter region.Functions as a stress-inducible potent transcriptional activator during endoplasmic reticulum (ER) stress by inducing unfolded protein response (UPR) target genes via binding to the UPR element (UPRE). Up-regulates target genes encoding ER chaperones and ER-associated degradation (ERAD) components to enhance the capacity of productive folding and degradation mechanism, respectively, in order to maintain the homeostasis of the ER under ER stress. Plays a role in the production of immunoglobulins and interleukin-6 in the presence of stimuli required for plasma cell differentiation (By similarity). Induces phospholipid biosynthesis and ER expansion. Contributes to the VEGF-induced endothelial cell (EC) growth and proliferation in a Akt/GSK-dependent and/or -independent signaling pathway, respectively, leading to beta-catenin nuclear translocation and E2F2 gene expression. Promotes umbilical vein EC apoptosis and atherosclerotisis development in a caspase-dependent signaling pathway, and contributes to VEGF-induced EC proliferation and angiogenesis in adult tissues under ischemic conditions. Involved in the regulation of endostatin-induced autophagy in EC through BECN1 transcriptional activation. Plays a role as an oncogene by promoting tumor progression: stimulates zinc finger protein SNAI1 transcription to induce epithelial-to-mesenchymal (EMT) transition, cell migration and invasion of breast cancer cells. Involved in adipocyte differentiation by regulating lipogenic gene expression during lactation. Plays a role in the survival of both dopaminergic neurons of the substantia nigra pars compacta (SNpc), by maintaining protein homeostasis and of myeloma cells. Increases insulin sensitivity in the liver as a response to a high carbohydrate diet, resulting in improved glucose tolerance. Improves also glucose homeostasis in an ER stress- and/or insulin-independent manner through both binding and proteasome-induced degradation of the transcription factor FOXO1, hence resulting in suppression of gluconeogenic genes expression and in a reduction of blood glucose levels. Controls the induction of de novo fatty acid synthesis in hepatocytes by regulating the expression of a subset of lipogenic genes in an ER stress- and UPR-independent manner (By similarity). Associates preferentially to the HDAC3 gene promoter region in a disturbed flow-dependent manner. Binds to the BECN1 gene promoter region. Binds to the CDH5/VE-cadherin gene promoter region. Binds to the ER stress response element (ERSE) upon ER stress. Binds to the 5'-CCACG-3' motif in the PPARG promoter (By similarity).

NCBI and Uniprot Product Information

• NCBI GI #: 47678753
• NCBI GeneID: 7494
• UniProt Accession #: P17861; Q8WYK6; Q969P1; Q96BD7
• Molecular Weight: 28,695 Da
• NCBI Official Full Name: XBP1
• NCBI Official Synonym Full Names: X-box binding protein 1
• NCBI Official Symbol: XBP1
• NCBI Official Synonym Symbols: XBP2; TREB5; XBP-1
• NCBI Protein Information: X-box-binding protein 1; tax-responsive element-binding protein 5
• UniProt Protein Name: X-box-binding protein 1
• Protein Family: X-box-binding protein
• UniProt Gene Name: XBP1
• UniProt Synonym Gene Names: TREB5; XBP2; XBP-1
• UniProt Entry Name: XBP1_HUMAN

NCBI Description

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]

Uniprot Description

XBP1: a transcription factor essential for hepatocyte growth, the differentiation of plasma cells, immunoglobulin secretion, and the unfolded protein response (UPR). XBP1 mRNA is spliced by IRE1 during the UPR to generate a new C-terminus, converting it into a potent unfolded-protein response transcriptional activator and triggering growth arrest and apoptosis. Only the spliced form of XBP1 can activate the UPR efficiently. Activates UPR target genes via direct binding to the UPR element (UPRE). Binds DNA preferably to the CRE-like element 5'-GATGACGTG[TG]N(3)[AT]T-3', and also to some TPA response elements (TRE). Binds to the HLA DR-alpha promoter. Binds to the Tax-responsive element (TRE) of HTLV-I. Up-regulated by ATF6 via direct binding to the ERSE in response to endoplasmic reticulum stress. Genetic variations in XBP1 could be associated with susceptibility to major affective disorder type 7 (MAFD7). Major affective disorders represent a class of mental disorders characterized by a disturbance in mood as their predominant feature. Two human isoforms are produced by alternative splicing. Isoform 1 is also known as XBP-1U. Isoform 2, also known as XBP-1S, is produced by IRE1 in response to endoplasmic reticulum stress. IRE1 cleaves a 26-bp fragment causing a frameshift of the mRNA transcript.

Protein type: Transcription factor; DNA-binding

Chromosomal Location of Human Ortholog: 22q12.1|22q12

Cellular Component: nucleoplasm; endoplasmic reticulum membrane; endoplasmic reticulum; cytoplasm; integral to membrane; integral to endoplasmic reticulum membrane; cytosol; nucleus

Molecular Function: protein binding; protein homodimerization activity; DNA binding; protease binding; chromatin DNA binding; protein heterodimerization activity; ubiquitin protein ligase binding; estrogen receptor binding; transcription factor activity; protein kinase binding

Biological Process: ubiquitin-dependent protein catabolic process; transcription from RNA polymerase II promoter; muscle development; phosphoinositide 3-kinase cascade; apoptosis; positive regulation of transcription of target genes involved in unfolded protein response; exocrine pancreas development; regulation of protein stability; negative regulation of transcription from RNA polymerase II promoter; cellular response to glucose starvation; protein transport; serotonin secretion, neurotransmission; positive regulation of MHC class II biosynthetic process; positive regulation of transcription factor import into nucleus; angiogenesis; cell growth; response to electrical stimulus; positive regulation of TOR signaling pathway; positive regulation of autophagy; fatty acid biosynthetic process; response to drug; positive regulation of histone methylation; protein destabilization; unfolded protein response; organelle organization and biogenesis; cellular response to nutrient; positive regulation of immunoglobulin secretion; liver development; positive regulation of immunoglobulin production; cholesterol homeostasis; unfolded protein response, activation of signaling protein activity; cellular protein metabolic process; cellular response to insulin stimulus; positive regulation of T cell differentiation; fatty acid homeostasis; endothelial cell proliferation; neuron development; positive regulation of fat cell differentiation; autophagy; positive regulation of B cell differentiation; positive regulation of transcription from RNA polymerase II promoter; immune response; positive regulation of protein amino acid phosphorylation; sterol homeostasis; vascular endothelial growth factor receptor signaling pathway; negative regulation of apoptosis

Disease: Major Affective Disorder 7