The Kinetic Response of the Proteome in A549 Cells Exposed to XXXX Stress.

@entity8862 @entity219 @entity5937 @entity15
@entity219 , an essential trace element, is involved in many important physiological processes. Cell responses to @entity219 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 @entity5937 for both 9 and 24 h using 2DE. 123 differentially expressed protein spots were detected, most of which were up-regulated by @entity8862 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 @entity219 treatment are always lower than that after 9 h, indicating that exogenous @entity219 reduced the expression of proteins in cells after 24 h or longer. Importantly, these findings could also reflect the central challenge in detecting @entity219 homeostasis proteins by 2DE or other high throughput analytical methods resulting from slight variation in protein expression after certain durations of exogenous @entity219 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 @entity219 and free @entity8862 ion contents in cells were measured using ICP- @entity15 and confocal microscopy, respectively. The kinetic process of @entity219 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 @entity219 stress and the mechanism of @entity219 homeostasis.
