Endoplasmic reticulum stress pathway mediators (ER stress pathway mediators)

Endoplasmic reticulum (ER) stress pathway mediators are a group of proteins that orchestrate the Unfolded Protein Response (UPR), a cellular adaptive mechanism activated when the protein-folding capacity of the ER is overwhelmed [1.1.1, 1.1.2]. The primary sensors of this pathway include Inositol-requiring enzyme 1 (IRE1), Protein kinase RNA-like endoplasmic reticulum kinase (PERK), and Activating transcription factor 6 (ATF6), which are normally sequestered in an inactive state by the chaperone GRP78 (BiP) [1.1.5, 1.3.1]. Upon the accumulation of misfolded proteins, GRP78 dissociates, allowing these sensors to initiate signaling cascades that reduce global protein synthesis, increase folding capacity, and enhance protein degradation [1.2.4, 1.3.2]. While the UPR initially serves a pro-survival function, chronic or severe ER stress can shift the response toward a terminal UPR that triggers apoptosis via mediators like CHOP [1.1.3, 1.2.3]. Dysregulation of these mediators is central to the pathogenesis of various conditions, including cancer, neurodegenerative diseases, and metabolic disorders like diabetes [1.1.1, 1.1.3]. Consequently, small-molecule inhibitors and activators targeting specific UPR branches, such as KIRA6 for IRE1 or GSK2606414 for PERK, are being developed as therapeutic strategies to either protect stressed cells or selectively eliminate malignant ones [1.2.5, 1.3.2].

Other names

Unfolded protein response (UPR) mediatorsER stress sensorsUPR signaling componentsER stress response proteins

Modulation of the unfolded protein response (UPR) by inhibiting or activating key sensors (PERK, IRE1, ATF6) to restore proteostasis or induce apoptosis in diseased cells [1.3.2, 1.2.5].