Endoplasmic reticulum stress pathway protein (null)

Endoplasmic reticulum stress pathway protein" is not a specific molecular target but rather refers collectively to several key transmembrane sensor proteins that mediate the cellular response known as the unfolded protein response (UPR). The main canonical sensors are **inositol-requiring enzyme 1** (*IRE1*), **protein kinase RNA-like endoplasmic reticulum kinase** (*PERK*), and **activating transcription factor 6** (*ATF6*)—each with distinct but overlapping roles. These sensors detect disturbances in protein folding within the endoplasmic reticulum lumen caused by physiological or pathological stresses. Upon activation, they initiate signaling cascades that reduce global protein synthesis, upregulate chaperone production like GRP78/BiP for improved folding capacity, promote degradation pathways for misfolded proteins, and can trigger apoptosis if homeostasis cannot be restored. Dysregulation or chronic activation of these pathways is implicated in diseases such as cancer, neurodegeneration, diabetes, infection-related pathologies and more. Several small molecules—including thapsigargin and tunicamycin—are used experimentally or therapeutically to modulate this system via different mechanisms.

Other names

ER stress pathway proteinUnfolded protein response (UPR) component (context-dependent)ER stress sensor (context-dependent)

Drugs targeting this pathway act by inducing or inhibiting ER stress through various mechanisms such as: - Inhibition of N-linked glycosylation of proteins (tunicamycin) - Disruption of calcium homeostasis in the ER lumen by inhibiting SERCA pumps (thapsigargin) - Inhibition of disulfide bond formation in proteins leading to misfolding accumulation (dithiothreitol) - Proteasome inhibition leading to accumulation of misfolded proteins and UPR activation/apoptosis induction in cancer cells (bortezomib)