Effect of proteasomal inhibitors on nicastrin expression in neuronal cells / 中国病理生理杂志

ABSTRACT

AIM: To explore the possibility that proteasome is involved in nicastrin(NCT) degradation and NCT is ubiquitinated before degradation.METHODS: Following the generation of NCT stable cell lines,the methods of Western blotting,pulse-chase metabolic labeling technique,double immunofluorescent staining,combined with proteasomal inhibition were used to investigate the NCT expression in NCT stable cell line.RESULTS: Treatment of the cells with proteasomal inhibitors significantly increased both endogenous NCT(produced by the cell itself) and exogenous NCT(produced by the gene transfection) in SH-SY5Y cells.The effect of specific proteasomal inhibitor lactacystin on NCT expression was in time-and dose-dependent manners.Pulse-chase metabolic labeling experiment showed that the turnover of newly-synthesized radio-labeled nicastrin protein was blocked by lactacystin.The results of double immunofluorescent staining showed that NCT and ubiquitin were co-located in the cells.CONCLUSION: The proteasome is involved in the degradation of NCT in neuronal cells,and NCT is ubiquitinated before degradation.