Calpain mediates processing of the translation termination factor eRF3 into the IAP-binding isoform p-eRF3.

Yoshifumi Hashimoto, Hiroto Inagaki, Shin-ichi Hoshino

Index: FEBS Lett. 589 , 2241-7, (2015)

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Abstract

The involvement of polypeptide chain-releasing factor eRF3 in translation termination and mRNA decay is well established. Moreover, the finding that the proteolytically processed isoform of eRF3 (p-eRF3) interacts with inhibitors of apoptosis proteins (IAPs) to activate caspase, implies that eRF3 is a cell death regulator. However, the protease(s) responsible for p-eRF3 production and how p-eRF3 regulates apoptosis remain unknown. Here, we show that calpain mediates p-eRF3 production in vitro and in living cells. p-eRF3 is produced in cells treated with ER stressors in a calpain-dependent manner. These findings suggest that p-eRF3 is a novel regulator of calpain-dependent cell death. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.