title: The Kinetic Response of the Proteome in A549 Cells Exposed to ZnSO4 Stress.
abstract: Zinc, an essential trace element, is involved in many important physiological processes. Cell responses to zinc stress show time-dependent effects besides concentration-dependence and tissue-specificity. Herein, we investigated the time-dependent differential expression of the proteome in A549 cells after administered with ZnSO4 for both 9 and 24 h using 2DE. 123 differentially expressed protein spots were detected, most of which were up-regulated by Zn2+ treatment. Interestingly, 49 proteins exhibited significant differential expression repeatedly during these two treatment periods, and moreover showed a conserved change with different ratios and four time-dependent expression patterns. Pattern 1 (up-regulated with rapid initial induction and subsequent repression) and pattern 4 (down-regulated with steady repression) were the predominant expression patterns. The abundances of the proteins in patterns 1 and 4 after 24 h of zinc treatment are always lower than that after 9 h, indicating that exogenous zinc reduced the expression of proteins in cells after 24 h or longer. Importantly, these findings could also reflect the central challenge in detecting zinc homeostasis proteins by 2DE or other high throughput analytical methods resulting from slight variation in protein expression after certain durations of exogenous zinc treatment and/or low inherent protein content in cells. These time-dependent proteome expression patterns were further validated by measuring dynamic changes in protein content in cells and in expression of two proteins using the Bradford method and western blotting, respectively. The time-dependent changes in total zinc and free Zn2+ ion contents in cells were measured using ICP-MS and confocal microscopy, respectively. The kinetic process of zinc homeostasis regulated by muffling was further revealed. In addition, we identified 50 differentially expressed proteins which are predominantly involved in metabolic process, cellular process or developmental process, and function as binding, catalytic activity or structural molecule activity. This study further elucidates our understanding of dynamic nature of the cellular response to zinc stress and the mechanism of zinc homeostasis.
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, Nanjing, Jiangsu, PR China.
authors.forename: Wen-Jie
authors.initials: WJ
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, Nanjing, Jiangsu, PR China.
authors.forename: Qun
authors.initials: Q
authors.lastname: Song
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, Nanjing, Jiangsu, PR China.
authors.forename: Zi-Jin
authors.initials: ZJ
authors.lastname: Zhang
authors.affiliation: MOE Key Laboratory of Modern Toxicology, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Mao
authors.affiliation: State Key Laboratory of Pharmaceutical Biotechnology, School of Life Science, Nanjing University, Nanjing, Jiangsu, PR China.
authors.forename: Wei-Juan
authors.initials: WJ
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, Nanjing, Jiangsu, PR China.
authors.forename: Xin
authors.initials: X
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, Nanjing, Jiangsu, PR China.
authors.forename: Hong-Zhen
authors.initials: HZ
authors.lastname: Lian
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects; D015180:Electrophoresis, Gel, Two-Dimensional; D006801:Humans; D007700:Kinetics; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology; D013058:Mass Spectrometry / Q000379:methods; D018613:Microscopy, Confocal; D020543:Proteome / Q000032:analysis* / Q000145:classification / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D013312:Stress, Physiological; D013997:Time Factors; D015854:Up-Regulation / Q000187:drug effects; D019287:Zinc Sulfate / Q000494:pharmacology*
chemical_list: D020543:Proteome; D019287:Zinc Sulfate