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X-box-binding protein 1; XBP-1; Tax-responsive element-binding protein 5 (XBP1, TREB5, XBP2)
Function:
- transcription factor essential for
a) hepatocyte growth
b) differentiation of plasma cells
c) immunoglobulin secretion
d) unfolded protein response
- acts during endoplasmic reticulum stress (ER) by activating unfolded protein response 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', & also to some TPA response elements (TRE)
- binds to the HLA DR-alpha promoter
- binds to the Tax-responsive element of HTLV-I
- potent transcriptional activator
- induced by ERN1 in response to an ER stress, which cleaves a 26-bp fragment inducing a frameshift of the mRNA transcript
Structure:
- belongs to the bZIP family
- contains 1 bZIP domain
Compartment: nucleus
Alternative splicing: named isoforms=2
Expression:
- up-regulated by ATF6 via direct binding to the ERSE in response to endoplasmic reticulum stress
General
basic leucine zipper (bZIP) family protein
Properties
SIZE: entity length = 261 aa
MW = 29 kD
COMPARTMENT: cell nucleus
MOTIF: DNA-binding motif
SITE: 72-94
leucine zipper
SITE: 98-126
FOR-BINDING-VIA: leucine zipper
Database Correlations
OMIM 194355
UniProt P17861
Pfam PF07716
Kegg hsa:7494
References
- UniProt :accession P17861
- Rampon C, Jiang CH, Dong H, Tang YP, Lockhart DJ, Schultz PG,
Tsien JZ, Hu Y.
Effects of environmental enrichment on gene expression in the
brain.
Proc Natl Acad Sci U S A. 2000 Nov 7;97(23):12880-4.
PMID: 11070096