Nck-dependent activation of extracellular signal-regulated kinase-1 and regulation of cell survival during endoplasmic reticulum stress

• Published in: Molecular biology of the cell 2004-09, Vol.15 (9), p.4248-4260
• Main Authors: Nguyên, Duc Thang, Kebache, Sem, Fazel, Ali, Wong, Hetty N, Jenna, Sarah, Emadali, Anouk, Lee, Eun-Hye, Bergeron, John J M, Kaufman, Randal J, Larose, Louise, Chevet, Eric
• Format: Article
• Language: English
• Subjects: Adaptor Proteins, Signal Transducing - genetics; Adaptor Proteins, Signal Transducing - metabolism; Animals; Azetidinecarboxylic Acid - pharmacology; Base Sequence; Cell Line; Cell Survival; DNA, Complementary - genetics; Endoplasmic Reticulum - drug effects; Endoplasmic Reticulum - metabolism; Enzyme Activation; MAP Kinase Signaling System - drug effects; Membrane Proteins - genetics; Membrane Proteins - metabolism; Mice; Mitogen-Activated Protein Kinase 3 - metabolism; Models, Biological; Oncogene Proteins - genetics; Oncogene Proteins - metabolism; Protein Serine-Threonine Kinases - genetics; Protein Serine-Threonine Kinases - metabolism; Rats; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Tunicamycin - pharmacology
• ISSN: 1059-1524; 1939-4586
• DOI: 10.1091/mbc.E03-11-0851

In response to stress, the endoplasmic reticulum (ER) signaling machinery triggers the inhibition of protein synthesis and up-regulation of genes whose products are involved in protein folding, cell cycle exit, and/or apoptosis. We demonstrate that the misfolding agents azetidine-2-carboxylic acid (Azc) and tunicamycin initiate signaling from the ER, resulting in the activation of Jun-N-terminal kinase, p44(MAPK)/extracellular signal-regulated kinase-1 (ERK-1), and p38(MAPK) through IRE1alpha-dependent mechanisms. To characterize the ER proximal signaling events involved, immuno-isolated ER membranes from rat fibroblasts treated with ER stress inducers were used to reconstitute the activation of the stress-activated protein kinase/mitogen-activate protein kinase (MAPK) pathways in vitro. This allowed us to demonstrate a role for the SH2/SH3 domain containing adaptor Nck in ERK-1 activation after Azc treatment. We also show both in vitro and in vivo that under basal conditions ER-associated Nck represses ERK-1 activation and that upon ER stress this pool of Nck dissociates from the ER membrane to allow ERK-1 activation. Moreover, under the same conditions, Nck-null cells elicit a stronger ERK-1 activation in response to Azc stress, thus, correlating with an enhanced survival phenotype. These data delineate a novel mechanism for the regulation of ER stress signaling to the MAPK pathway and demonstrate a critical role for Nck in ER stress and cell survival.