title: Knockdown of ERp44 leads to apoptosis via activation of ER stress in HeLa cells.
abstract: ERp44, an endoplasmic reticulum (ER) resident protein, regulates intracellular Ca(2+) release and involves in the maturation of many proteins in mammalian cells. In this study, we investigated the effects and mechanism of ERp44 on cell apoptosis by using ERp44 knockdown stable HeLa cell lines. We found that ERp44 knockdown resulted in increases in cell apoptosis rate more than one fold higher than that of control; using serum starvation, caspase-3 protein level was significantly up-regulated in ERp44 knockdown cells compared to the control cells. Furthermore, we demonstrated that in response to serum starvation, the protein levels of CHOP and GRP78 were also largely raised in ERp44 knockdown cells. Moreover, caspase-12 was activated, which suggested cell apoptosis was induced by ER stress. Taken together, our results indicate that knockdown of ERp44 leads to cell apoptosis through the activation of ER stress.
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Chang
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
authors.forename: Yanyun
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Pharmacology, Jilin Medical College, Jilin, China. Electronic address: liuwei1606@163.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China. Electronic address: gj28@ibp.ac.cn.
authors.forename: Guangju
authors.initials: G
authors.lastname: Ji
mesh_terms: D017209:Apoptosis / Q000235:genetics*; D002118:Calcium / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D000091342:Endoplasmic Reticulum Chaperone BiP; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D018832:Molecular Chaperones / Q000235:genetics / Q000502:physiology*; D018384:Oxidative Stress
chemical_list: C451899:ERP44 protein, human; D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; D008565:Membrane Proteins; D018832:Molecular Chaperones; D002118:Calcium
keywords: Ca(2+) oscillation; Cell apoptosis; ER stress; ERp44