title: Nck-dependent activation of extracellular signal-regulated kinase-1 and regulation of cell survival during endoplasmic reticulum stress.
abstract: 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.
authors.affiliation: Department of Surgery, McGill University, Montreal, Quebec, H3A 1A1 Canada.
authors.forename: Duc Thang
authors.initials: DT
authors.lastname: Nguyên
authors.forename: Sem
authors.initials: S
authors.lastname: Kebache
authors.forename: Ali
authors.initials: A
authors.lastname: Fazel
authors.forename: Hetty N
authors.initials: HN
authors.lastname: Wong
authors.forename: Sarah
authors.initials: S
authors.lastname: Jenna
authors.forename: Anouk
authors.initials: A
authors.lastname: Emadali
authors.forename: Eun-Hye
authors.initials: EH
authors.lastname: Lee
authors.forename: John J M
authors.initials: JJ
authors.lastname: Bergeron
authors.forename: Randal J
authors.initials: RJ
authors.lastname: Kaufman
authors.forename: Louise
authors.initials: L
authors.lastname: Larose
authors.forename: Eric
authors.initials: E
authors.lastname: Chevet
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001383:Azetidinecarboxylic Acid / Q000494:pharmacology; D001483:Base Sequence; D002460:Cell Line; D002470:Cell Survival; D018076:DNA, Complementary / Q000235:genetics; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism*; D004789:Enzyme Activation; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D008954:Models, Biological; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014415:Tunicamycin / Q000494:pharmacology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D018076:DNA, Complementary; D008565:Membrane Proteins; C078332:Nck protein; C117758:Nck2 protein, mouse; D015513:Oncogene Proteins; D011993:Recombinant Fusion Proteins; D014415:Tunicamycin; D001383:Azetidinecarboxylic Acid; C486556:Ern2 protein, mouse; D017346:Protein Serine-Threonine Kinases; D048052:Mitogen-Activated Protein Kinase 3