The Human (ERN1) Serine Threonine-protein Kinase Endoribonuclease Ire1 ELISA Kit measures Serine/threonine-protein kinase/endoribonuclease IRE1 in samples. The plate has been pre-coated with Human ERN1 antibody. ERN1 present in the sample is added and binds to antibodies coated on the wells. And then biotinylated Human ERN1 Antibody is added and binds to ERN1 in the sample. Then Streptavidin-HRP is added and binds to the Biotinylated ERN1 antibody. After incubation unbound Streptavidin-HRP is washed away during a washing step. Substrate solution is then added and color develops in proportion to the amount of Human ERN1. The reaction is terminated by addition of acidic stop solution and absorbance is measured at 450 nm.
Research AreasSignal Transduction, Enzyme & Kinase
BackgroundSerine/threonine-protein kinase and endoribonuclease that acts as a key sensor for the endoplasmic reticulum unfolded protein response (UPR) (PubMed:11779464, PubMed:11175748, PubMed:12637535, PubMed:9637683, PubMed:21317875, PubMed:28128204).
In unstressed cells, the endoplasmic reticulum luminal domain is maintained in its inactive monomeric state by binding to the endoplasmic reticulum chaperone HSPA5/BiP (PubMed:21317875).
Accumulation of misfolded proteins 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 (PubMed:21317875).
The endoribonuclease activity is specific for XBP1 mRNA and excises 26 nucleotides from XBP1 mRNA (PubMed:11779464, PubMed:24508390, PubMed:21317875).
The resulting spliced transcript of XBP1 encodes a transcriptional activator protein that up-regulates expression of UPR target genes (PubMed:11779464, PubMed:24508390, PubMed:21317875).
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 (PubMed:21884936, PubMed:28067262). Source: UniProt Consortium (2025)
