Shen X, Ellis RE, Sakaki K and Kaufman RJ. Genetic interactions due to constitutive and inducible gene regulation mediated by the unfolded protein response in C. elegans. PLOS GENETICS 1(3):e37, 2005

Abstract The unfolded protein response (UPR) is an adaptive signaling pathway utilized to sense and alleviate the stress of protein folding in the endoplasmic reticulum (ER). In mammals, the UPR is mediated through three proximal sensors PERK/PEK, IRE1, and ATF6. PERK/PEK is a protein kinase that phosphorylates the alpha subunit of eukaryotic translation initiation factor 2 to inhibit protein synthesis. Activation of IRE1 induces splicing of XBP1 mRNA to produce a potent transcription factor. ATF6 is a transmembrane transcription factor that is activated by cleavage upon ER stress. We show that in Caenorhabditis elegans, deletion of either ire-1 or xbp-1 is synthetically lethal with deletion of either atf-6 or pek-1, both producing a developmental arrest at larval stage 2. Therefore, in C......