Functions as a transcription factor during endoplasmic reticulum stress by regulating the unfolded protein response . Required for cardiac myogenesis and hepatogenesis during embryonic development, and the development of secretory tissues such as exocrine pancreas and salivary gland . 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 proliferation and retinal blood vessel formation during embryonic development but also for angiogenesis in adult tissues under ischemic conditions. Also functions as a major regulator of the UPR in obesity-induced insulin resistance and type 2 diabetes for the management of obesity and diabetes prevention . ; [Isoform 1]: Plays a role in the unconventional cytoplasmic splicing processing of its own mRNA triggered by the endoplasmic reticulum transmembrane endoribonuclease ERN1: upon ER stress, the emerging XBP1 polypeptide chain, as part of a mRNA-ribosome-nascent chain 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 , associated with KDR, promotes IRE1-mediated XBP1 mRNA isoform 2 productions in a vascular endothelial growth factor -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 . Acts as a weak transcriptional factor . Together with HDAC3, contributes to the activation of NFE2L2-mediated HMOX1 transcription factor gene expression in a PIK/mTORC2/Akt-dependent signaling pathway leading to EC survival under disturbed flow/oxidative stress . Binds to the ER stress response element upon ER stress . Binds to the consensus 5'-GATGACGTG[TG]N[AT]T-3' sequence related to cAMP responsive element -like sequences . Binds the Tax-responsive element present in the long terminal repeat of T-cell leukemia virus type 1 and to the TPA response elements . Associates preferentially to the HDAC3 gene promoter region in a static flow-dependent manner . Binds to the CDH5/VE-cadherin gene promoter region . ; [Isoform 2]: Functions as a stress-inducible potent transcriptional activator during endoplasmic reticulum stress by inducing unfolded protein response target genes via binding to the UPR element . Up-regulates target genes encoding ER chaperones and ER-associated degradation 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 . Induces phospholipid biosynthesis and ER expansion . Contributes to the VEGF-induced endothelial cell 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 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 , 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. Also improves 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 . 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 upon ER stress . Binds to the 5'-CCACG-3' motif in the PPARG promoter .

X-box-binding protein 1 (XBP-1) (Tax-responsive element-binding protein 5) (TREB-5) [Cleaved into: X-box-binding protein 1, cytoplasmic form; X-box-binding protein 1, luminal form]

p17861

Human,Mouse

WB,IP,FC

WB 1:1000
IP 1:50
FC 1:100

~29 kD

Rabbit

50mM Tris-Glycine(pH 7.4), 0.15M NaCl, 40% Glycerol, 0.01% sodium azide and 0.05% BSA.

Store at -20°C. Stable for 12 months from date of receipt.