Kota Yanagitani

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Upon endoplasmic reticulum (ER) stress, an endoribonuclease, inositol-requiring enzyme-1α, splices the precursor unspliced form of X-box-binding protein 1 messenger RNA (XBP1u mRNA) on the ER membrane to yield an active transcription factor (XBP1s), leading to the alleviation of the stress. The nascent peptide encoded by XBP1u mRNA drags the(More)
Endoplasmic reticulum (ER) stress triggers the cytoplasmic splicing of XBP1 mRNA by the transmembrane endoribonuclease IRE1alpha, resulting in activation of the unfolded protein response, which maintains ER homeostasis. We show that the unspliced XBP1 (XBP1u) mRNA is localized to the membrane, although its product is neither a secretory nor a membrane(More)
Upon endoplasmic reticulum (ER) stress, mammalian cells induce the synthesis of a transcriptional activator XBP1s to alleviate the stress. Under unstressed conditions, the messenger RNA (mRNA) for XBP1s exists in the cytosol as an unspliced precursor form, XBP1u mRNA. Thus, its intron must be removed for the synthesis of XBP1s. Upon ER stress, a stress(More)
Unconventional mRNA splicing on the endoplasmic reticulum (ER) membrane is the sole conserved mechanism in eukaryotes to transmit information regarding misfolded protein accumulation to the nucleus to activate the stress response. In metazoans, the unspliced form of X-box-binding protein 1 (XBP1u) mRNA is recruited to membranes as a ribosome nascent chain(More)
Many nascent proteins are assembled into multiprotein complexes of defined stoichiometry. Imbalances in the synthesis of individual subunits result in orphans. How orphans are selectively eliminated to maintain protein homeostasis is poorly understood. Here, we found that the conserved ubiquitin-conjugating enzyme UBE2O directly recognized juxtaposed basic(More)
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