title: IRE1α nucleotide sequence cleavage specificity in the unfolded protein response.
abstract: Inositol-requiring enzyme 1 (IRE1) is a conserved sensor of the unfolded protein response that has protein kinase and endoribonuclease (RNase) enzymatic activities and thereby initiates HAC1/XBP1 splicing. Previous studies demonstrated that human IRE1α (hIRE1α) does not cleave Saccharomyces cerevisiae HAC1 mRNA. Using an in vitro cleavage assay, we show that adenine to cytosine nucleotide substitution at the +1 position in the 3' splice site of HAC1 RNA is required for specific cleavage by hIRE1α. A similar restricted nucleotide specificity in the RNA substrate was observed for XBP1 splicing in vivo. Together these findings underscore the essential role of cytosine nucleotide at +1 in the 3' splice site for determining cleavage specificity of hIRE1α.
authors.affiliation: The Institute of Molecular Biosciences, Mahidol University, Salaya, Thailand.|Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.
authors.forename: Juthakorn
authors.initials: J
authors.lastname: Poothong
authors.affiliation: The Institute of Molecular Biosciences, Mahidol University, Salaya, Thailand.
authors.forename: Pattarawut
authors.initials: P
authors.lastname: Sopha
authors.affiliation: Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.
authors.forename: Randal J
authors.identifier: 0000-0003-4277-316X
authors.initials: RJ
authors.lastname: Kaufman
authors.affiliation: The Institute of Molecular Biosciences, Mahidol University, Salaya, Thailand.
authors.forename: Witoon
authors.initials: W
authors.lastname: Tirasophon
mesh_terms: D000818:Animals; D001483:Base Sequence; D050976:Basic-Leucine Zipper Transcription Factors / Q000378:metabolism; D019556:COS Cells; D002522:Chlorocebus aethiops; D003596:Cytosine / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D029721:Drosophila Proteins / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics; D004722:Endoribonucleases / Q000378:metabolism*; D006801:Humans; D009690:Nucleic Acid Conformation; D009711:Nucleotides / Q000378:metabolism; D017354:Point Mutation / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D022821:RNA Splice Sites / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D015398:Signal Transduction; D056811:Unfolded Protein Response
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; C091341:HAC1 protein, S cerevisiae; D009711:Nucleotides; D022821:RNA Splice Sites; D012333:RNA, Messenger; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; C517798:Xbp1 protein, Drosophila; D003596:Cytosine; C528229:ERN1 protein, human; D017346:Protein Serine-Threonine Kinases; D004722:Endoribonucleases
keywords: HAC1; IRE1; RNase; XBP1