Heat Shock Proteins and Endoplasmic Reticulum Stress

Abstract

The endoplasmic reticulum (ER) is a dynamic as well as an intricate organelle that carries out diverse essential functions within the cell. The efficient functions of the ER regulate the cellular processes and maintain cell homeostasis. When this dynamic equilibrium gets imbalanced due to perturbations in the ER functions, a condition termed ER stress occurs. ER stress accumulates and aggregates unfolded proteins within the ER lumen. An evolutionarily conserved signal transduction mechanism called unfolded protein response (UPR) recuperates the ER function and proteostasis in the ER. A diverse group of heat shock proteins (HSP) has been implicated in this ER stress response. In recent years, studies have revealed the roles of HSP in sensing the ER stress and activating the three axes of UPR. In addition, the HSP are also responsible for the ER associated degradation of unfolded proteins when ER stress persists for a long time. The HSP in ER stress have been implicated in diverse pathophysiological conditions like cardiovascular diseases, cancer, aging, diabetes and obesity. In the present chapter, we have summarized the advances made in the manifold roles of HSP that govern ER stress signaling in health.