... XBP1 PERK eIF2α ATF4 ATF6 Pancreas Eye In eukaryotic cells, the endoplasmic reticulum (ER) serves as the primary site of folding and maturation of secretory and transmembrane proteins. Nascent polypeptides undergo a complex, multistep chaperone-assisted process of maturation to attain...

...Huai-Wei Huang; Xiaomei Zeng; Taiyoun Rhim; David Ron; Hyung Don Ryoo ABSTRACT IRE1 mediates the unfolded protein response (UPR) in part by regulating XBP1 mRNA splicing in response to endoplasmic reticulum (ER) stress. In cultured metazoan cells, IRE1 also exhibits XBP1-independent biochemical...

...Aya Uemura; Masaya Oku; Kazutoshi Mori; Hiderou Yoshida XBP1 is a key transcription factor that regulates the mammalian unfolded protein response. Its expression is regulated by unconventional mRNA splicing that is carried out by endonuclease IRE1 and a specific, as yet unknown, RNA ligase...

... set of signaling mechanisms triggered by increased demands on the protein folding capacity of the ER. The UPR transcriptional activator X-box binding protein 1 (XBP1) regulates the expression of proteins that function throughout the secretory pathway and is necessary for development of an expansive ER...