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ER Stress, Human Health and Role of Ca2+-Binding Chaperones
Date Issued
2018
Author(s)
Narayanasamy, S
Aradhyam, GK
Abstract
The Endoplasmic Reticulum (ER) is a dynamic and versatile organelle involved in many critical functions of the cell. It is the major Ca2+ storehouse of the cell and the intra luminal [Ca2+] influences several cellular processes including synthesis of protein, lipids and sterols. Therefore, the concentration of Ca2+ is tightly controlled and buffered by several Ca2+-binding proteins in the ER. Several physiological and pathological disturbances can also perturb ER homeostasis, leading to the accumulation of misfolded or unfolded proteins, a condition termed as ER stress. The ER responds well to the stress by activating a series of signaling cascades known as unfolded protein response (UPR) in order to rescue ER functions. The adaptive response of the UPR pathway activates the transcription of several genes including molecular chaperones which aid in the folding of misfolded proteins. In addition to Ca2+-binding (that regulates their function), these ER-resident calcium binding proteins play a major role in folding, post translational processing and quality control of other nascent polypeptide chains and hence can be classified as calcium-binding chaperones (CaBC). The role of CaBC in the UPR pathway is quite indispensable and will be discussed in this chapter.
Volume
13