The unfolded protein response sensor/transducer IRE1-mediated splicing of XBP1 mRNA encoding its active downstream transcription factor to maintain the homeostasis of the endoplasmic reticulum is sufficient for growth and development of medaka fish.
A genetic screen in a unicellular photosynthetic organism uncovers the first essential signaling component in the chloroplast unfolded protein response that relays information from the chloroplast to the nuclear compartment.
ER-stress sensing mechanism of the unfolded protein response sensor/transducer IRE1 is conserved from yeast to mammals, where in mammals, unfolded protein binding to IRE1's ER lumenal domain is coupled to its oligomerization and activation through an allosteric conformational change.
Feedback mechanisms that contribute to the deactivation of the unfolded protein response lead to the dysregulation of mRNA expression during chronic stress in the liver, including that of the critical endoplasmic reticulum chaperone BiP.
The extent of (proteotoxic) endoplasmic reticulum stress, and the ensuing unfolded protein response activation, are commensurate with the extent of the chaperone BiP being sequestered by its client proteins.