IRE1alpha hydrolyzes Xbp1 mRNA and Xbp1 mRNA is spliced

Stable Identifier
R-HSA-425923
Type
Reaction [omitted]
Species
Homo sapiens
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Phosphorylated IRE1-alpha homodimers with bound ADP have endoribonuclease activity in their C-terminal (cytosolic) regions. The IRE1-alpha homodimers cleave an internal 26 nucleotide segment out of the Xbp-1 mRNA. In yeast the resulting RNAs are ligated by a tRNA ligase but the corresponding human ligase has not been identified. The cleavage and ligation leads to a frameshift in the Xbp-1 mRNA which results in a longer ORF that encodes Xbp-1 (S), the active form of the Xbp-1 transcription factor

Literature References
PubMed ID Title Journal Year
17026957 Analysis of the XBP1 splicing mechanism using endoplasmic reticulum stress-indicators

Iwawaki, T, Akai, R

Biochem Biophys Res Commun 2006
11779464 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 2001
18242182 RNase domains determine the functional difference between IRE1alpha and IRE1beta

Imagawa, Y, Hosoda, A, Sasaka, S, Tsuru, A, Kohno, K

FEBS Lett 2008
19622636 Unconventional splicing of XBP1 mRNA occurs in the cytoplasm during the mammalian unfolded protein response

Uemura, A, Oku, M, Mori, K, Yoshida, H

J Cell Sci 2009
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Catalyst Activity
Title
endoribonuclease activity of p-S724-IRE1 dimer:ADP [endoplasmic reticulum membrane]
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