2021年7月8日 · The spliced form of X-box binding protein 1 (XBP1s) is an active transcription factor that plays a vital role in the unfolded protein response (UPR). Under endoplasmic reticulum (ER) stress, unspliced Xbp1 mRNA is cleaved by the activated stress sensor IRE1α and converted to the mature form encoding spliced XBP1 (XBP1s). Translated XBP1s ...

The spliced Xbp1 mRNA is translated by frameshift into an active transcription factor, XBP1s. Then, XBP1s upregulates the expression of UPR target genes, including ER chaperones, ERAD components, and lipid biosynthetic enzymes.

2014年12月17日 · Active UPR signaling leads to unconventional, enzymatic splicing of XBP1 mRNA enabling expression of the transcription factor XBP1s to control ER homeostasis. While IRE1 has been identified as the endoribonuclease required for cleavage of this mRNA, the corresponding ligase in mammalian cells has remained elusive.

2019年7月22日 · X-box binding protein 1 (XBP1) mRNA processing plays a crucial role in the unfolded protein response (UPR), which is activated in response to endoplasmic reticulum (ER) stress. Upon accumulation of the UPR-converted XBP1 mRNA splicing from an unspliced (u) XBP1 (inactive) isoform to the spliced (s) …

2001年12月28日 · Here, we identified the transcription factor XBP1, a target of ATF6, as a mammalian substrate of such an unconventional mRNA splicing system and showed that only the spliced form of XBP1 can activate the UPR efficiently.

2016年4月7日 · IRE1α has been known to splice X-box binding protein 1 (XBP1) mRNA, which is induced by ATF6 under ER stress. This spliced XBP1 mRNA is translated into the active transcription factor that...

2021年10月12日 · IRE1 activates a transcription factor, X-box-binding protein 1 (XBP1), by removing a 26-base intron from XBP1 mRNA that generates spliced XBP1 mRNA (XBP1s). To search for XBP1 transcriptional targets, we utilized an XBP1s-inducible human cell line to limit XBP1 expression in a controlled manner.

2022年3月24日 · We show that Pumilio protects Drosophila Xbp1 against RIDD, without perturbing canonical Ire1-driven Xbp1 splicing. Furthermore, we provide evidence that Ire1 phosphorylates Pumilio under ER...

Activated IRE1 catalyses the excision of a 26 nucleotide unconventional intron from ubiquitously expressed XBP1u mRNA, in a manner mechanistically similar to pre-tRNA splicing. Removal of this intron causes a frame shift in the XBP1 coding sequence resulting in the translation of a 376 amino acid, 40 kDa, XBP-1s isoform rather than the 261 ...

2001年12月28日 · Here, we identified the transcription factor XBP1, a target of ATF6, as a mammalian substrate of such an unconventional mRNA splicing system and showed that only the spliced form of XBP1 can activate the UPR efficiently.