XBP1 Rabbit Polyclonal Antibody

Function

X-box-binding protein 1 is a transcription factor essential for hepatocyte growth, the differentiation of plasma cells, the immunoglobulin secretion, and the unfolded protein response (UPR). It acts during endoplasmic reticulum stress (ER) by activating unfolded protein response (UPR) target genes via direct binding to the UPR element (UPRE). XBP1 binds DNA preferably to the CRE-like element 5'-GATGACGTG[TG]N3[AT]T-3', and also to some TPA response elements (TRE). A major psychiatric disorder that is characterized by severe mood swings, with fluctuation between two abnormal mood states (manic or major depressive episode).

Background References

1. "Impaired feedback regulation of XBP1 as a genetic risk factor for bipolar disorder." Kakiuchi C., Iwamoto K., Ishiwata M., Bundo M., Kasahara T., Kusumi I., Tsujita T., Okazaki Y., Nanko S., Kunugi H., Sasaki T., Kato T. Nat. Genet. 35:171-175(2003)

2. "XBP1 mRNA is induced by ATF6 and spliced by IRE1 in response to ER stress to produce a highly active transcription factor." Yoshida H., Matsui T., Yamamoto A., Okada T., Mori K. Cell 107:881-891(2001)

Sequence Similarity

Belongs to the bZIP family.

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.

Post-translational Modification

[Isoform 2]: 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]: 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.

Subcellular Location

Nucleus

UNIPROT

SwissProt: P17861 Human

Synonyms