Open AccessCharacterization of Stanniocalcin 2, a Novel Target of the Mammalian Unfolded Protein Response with Cytoprotective Properties
Author(s) -
Daisuke Ito,
John R. Walker,
C. S. Thompson,
Isabella Moroz,
Woei Lin,
Margaret Veselits,
Antoine M. Hakim,
Allen A. Fienberg,
Shuai Wang
Publication year - 2004
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.24.21.9456-9469.2004
Subject(s) - unfolded protein response , thapsigargin , biology , microbiology and biotechnology , endoplasmic reticulum , downregulation and upregulation , atf4 , tunicamycin , integrated stress response , programmed cell death , eif 2 kinase , apoptosis , protein kinase a , kinase , messenger rna , translation (biology) , gene , biochemistry , cyclin dependent kinase 2
Accumulation of misfolded proteins in the endoplasmic reticulum (ER) induces a highly conserved homeostatic response in all eukaryotic cells, termed the unfolded-protein response (UPR). Here we describe the characterization of stanniocalcin 2 (STC2), a mammalian homologue of a calcium- and phosphate-regulating hormone first identified in fish, as a novel target of the UPR. Expression of STC2 gene is rapidly upregulated in cultured cells after exposure to tunicamycin and thapsigargin, by ATF4 after activation of the ER-resident kinase PERK. In addition, STC2 expression is also activated in neuronal cells by oxidative stress and hypoxia but not by several cellular stresses unrelated to the UPR. In contrast, expression of another homologue, STC1, is only upregulated by hypoxia independent of PERK or ATF4 expression. In vivo studies revealed that rat cortical neurons rapidly upregulate STC2 after transient middle cerebral artery occlusion. Finally, siRNA-mediated inhibition of STC2 expression renders N2a neuroblastoma cells and HeLa cells significantly more vulnerable to apoptotic cell death after treatment with thapsigargin, and overexpression of STC2 attenuated thapsigargin-induced cell death. Consequently, induced STC2 expression is an essential feature of survival component of the UPR.