Endoplasmic reticulum proteins quality control and the unfolded protein response: The regulative mechanism of organisms against stress injuries

Abstract

The endoplasmic reticulum is the cellular compartment in which secretory proteins are synthesized and folded. Perturbations of endoplasmic reticulum homeostasis lead to the accumulation of unfolded proteins. The activation of the unfolded protein response during endoplasmic reticulum stress transmits information about the status of protein folding to the cytosol and nucleus. The unfolded protein response leads to the upregulation of genes encoding endoplasmic reticulum chaperones, attenuation of translation, and initiation of the endoplasmic reticulum quality control system to restore endoplasmic reticulum homeostasis. When the unfolded protein response is insufficient to rebuild the steady state in endoplasmic reticulum, the programmed cell death or apoptosis would be initiated, by triggering cell injuries, even to cell death through apoptosis signals. In this review, we briefly outline research on the chaperones and foldases conserved in eukaryotes and plants, and describe the general principles and mechanisms of the endoplasmic reticulum quality control and the unfolded protein response. We describe the current models for the molecular mechanism of the unfolded protein response in plants, and emphasize the role of inositol requiring enzyme-1-dependent network in the unfolded protein response. Finally, we give a general overview of the directions for future research on the unfolded protein response in plants and its role in the response to environmental stresses.

Oxidative Stress and Endoplasmic Reticulum Stress Are Involved in the Protective Effect of Alpha Lipoic Acid Against Heat Damage in Chicken Testes

“…The accumulation of unfolded or misfolded proteins in the ER lumen then triggers the ER stress response [6]. As showed in previous studies, ER stress is considered to be a protective response and it plays an important role in maintaining or restoring normal physiological function to cells during the early stages of stress or damage [7,8]. However, persistent or severe ER stress leads to apoptosis [9].…”

Arabidopsis thaliana intramembrane proteases

“…The S1P/S2P-dependent activation of bZIP17 also occurs in response to salt stress. It is thought that in this case the bZIP17 relocation and processing are activated by accumulation, in endoplasmic reticulum, of unfolded or misfolded proteins as part of a mechanism known as unfolded protein response (UPR) (Fu and Gao 2014;Liu et al 2007). The bZIP17N-terminal domain released by proteolytic cleavage is translocated to the nucleus where in cooperation with bZIP60 it activates salt stress-responsive and ER stress-induced genes (Silva et al 2015).…”

Dicot-specific ATG8-interacting ATI3 proteins interact with conserved UBAC2 proteins and play critical roles in plant stress responses

“…Effect of heat and UBAC2 on ATI3-and ATG8-labeled punctate structures Under stress conditions, misfolded proteins in the ER increase, causing ER stress. To overcome the problem, the unfolded protein response is activated for increased production of specific ER-resident proteins including the BIP (binding protein) family of molecular chaperones, which assist in protein folding and refolding [41,42]. As part of the unfolded protein response, ERAD is activated to remove misfolded proteins by delivery to the cytoplasm for proteasomal degradation [40].…”