Lipid biosynthesis and the unfolded protein response

XBP1: a link between the unfolded protein response, lipid biosynthesis, and biogenesis of the endoplasmic reticulum

hen the protein folding capacity of the endoplasmic reticulum (ER) is challenged, the unfolded protein response (UPR) maintains ER homeostasis by regulating protein synthesis and enhancing expression of resident ER proteins that facilitate protein maturation and degradation. Here, we report that enforced expression of XBP1(S), the active form of the XBP1 transcription factor generated by UPR-me...

Lipid-dependent regulation of the unfolded protein response

Protein folding homeostasis in the lumen of the endoplasmic reticulum is defended by signal transduction pathways that are activated by an imbalance between unfolded proteins and chaperones (so called ER stress). Collectively referred to as the unfolded protein response (UPR) this homeostatic response is initiated by three known ER stress transducers: IRE1, PERK and ATF6. These ER-localised tra...

The unfolded protein response

Where does the UPR function? Between the endoplasmic reticulum (ER) and the nucleus of eukaryotic cells. All secreted proteins and proteins that reside in secretory compartments translocate as nascent peptide chains into the ER, where they may undergo folding, modification and assembly before assuming their functional conformations. The ER maintains a specialized oxidizing environment to aid ch...

The unfolded protein response.

The endoplasmic reticulum (ER) is a principal site for folding and maturation of transmembrane, secretory and ERresident proteins. Perturbations that alter ER homeostasis can lead to accumulation of unfolded proteins (UPs), which is a threat to all living cells. To cope with the stress, cells activate an intracellular signaling pathway – the unfolded protein response (UPR). The UPR is an integr...

SnapShot: The Unfolded Protein Response