LCN2 null mice are sensitive to endoplasmic reticulum stress and unfolded protein responses

Unfolded protein response (UPR) is an adaptive response, allowing the endoplasmic reticulum (ER) responds to an accumulation of unfolded proteins in its lumen, also known as ER stress. The ER reacts to ER stress through ER transmembrane protein sensors, thus activating intracellular signal transduction pathways. The UPR is interconnected with inflammation through reactive oxygen species production, activation of nuclear factor-kB (NF-kB) and JUN N-terminal kinase (JNK) via inositol-requiring enzyme 1 (IRE1) and induction of acute-phase response. LCN2 is one of the acute phase proteins that are induced under inflammatory conditions and up-regulated during ER stress. We therefore examined the ER stress responses in LCN2-/- condition.