IRE1 Serine/threonine-protein kinase and endoribonuclease that acts as a key sensor for the endoplasmic reticulum unfolded protein response (UPR). In unstressed cells, the endoplasmic reticulum luminal domain is maintained in its inactive monomeric state by binding to the endoplasmic reticulum chaperone HSPA5/BiP. Accumulation of misfolded protein in the endoplasmic reticulum causes release of HSPA5/BiP, allowing the luminal domain to homodimerize, promoting autophosphorylation of the kinase domain and subsequent activation of the endoribonuclease activity. The endoribonuclease activity is specific for XBP1 mRNA and excises 26 nucleotides from XBP1 mRNA. The resulting spliced transcript of XBP1 encodes a transcriptional activator protein that up-regulates expression of UPR target genes. Acts as an upstream signal for ER stress-induced GORASP2-mediated unconventional (ER/Golgi-independent) trafficking of CFTR to cell membrane by modulating the expression and localization of SEC16A. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. Ubiquitously expressed. High levels observed in pancreatic tissue. 2 alternatively spliced human isoforms have been reported. Note: This description may include information from UniProtKB.
Protein type: Apoptosis; Chaperone; EC; Endoplasmic reticulum; IRE family; Kinase, protein; Membrane protein, integral; Other group; Protein kinase, Other; Protein kinase, Ser/Thr (non-receptor); Ribonuclease
Chromosomal Location of human Ortholog: 17q23.3
Cellular Component:  AIP1-IRE1 complex; cytoplasm; endoplasmic reticulum; endoplasmic reticulum membrane; Ire1 complex; IRE1-RACK1-PP2A complex; IRE1-TRAF2-ASK1 complex; mitochondrion; nuclear inner membrane
Molecular Function:  ADP binding; ATP binding; enzyme binding; Hsp70 protein binding; Hsp90 protein binding; identical protein binding; magnesium ion binding; platelet-derived growth factor receptor binding; protein binding; protein homodimerization activity; protein serine kinase activity; protein serine/threonine kinase activity; RNA endonuclease activity; unfolded protein binding
Biological Process:  cellular response to glucose stimulus; cellular response to hydrogen peroxide; cellular response to unfolded protein; cellular response to vascular endothelial growth factor stimulus; endothelial cell proliferation; insulin metabolic process; intrinsic apoptotic signaling pathway in response to endoplasmic reticulum stress; IRE1-mediated unfolded protein response; mRNA catabolic process; mRNA splicing, via endonucleolytic cleavage and ligation; peptidyl-serine autophosphorylation; peptidyl-serine trans-autophosphorylation; positive regulation of endoplasmic reticulum unfolded protein response; positive regulation of JUN kinase activity; positive regulation of RNA splicing; positive regulation of vascular associated smooth muscle cell proliferation; protein autophosphorylation; protein phosphorylation; regulation of macroautophagy; response to endoplasmic reticulum stress
Reference #:  O75460 (UniProtKB)
Alt. Names/Synonyms: endoplasmic reticulum to nucleus signaling 1; endoplasmic reticulum to nucleus signalling 1; Endoplasmic reticulum-to-nucleus signaling 1; Endoribonuclease; ER to nucleus signalling 1; ERN1; FLJ30999; hIRE1p; inositol-requiring 1; inositol-requiring enzyme 1; Inositol-requiring protein 1; IRE1; Ire1-alpha; IRE1a; IRE1P; MGC163277; MGC163279; protein kinase/endoribonuclease; Serine/threonine-protein kinase; Serine/threonine-protein kinase/endoribonuclease IRE1
Gene Symbols: ERN1
Molecular weight: 109,735 Da
Basal Isoelectric point: 5.98  Predict pI for various phosphorylation states
Protein-Specific Antibodies, siRNAs or Recombinant Proteins from Cell Signaling Technology® Total Proteins
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Protein Structure Not Found.

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