Expression of K6W-ubiquitin inhibits proliferation of human lensepithelial cells

[摘要] Purpose: The ubiquitin-proteasome pathway plays an important role incontrolling the cell cycle. The purpose of this study was to examine ifexpression of a dominant negative form of ubiquitin can inhibit theproliferation of lens epithelial cells.Methods: Dominant negative K6W-ubiquitin was expressed in culturedhuman lens epithelial cells via an adenoviral vector. Cell proliferationwas monitored by both cell counting and flow cytometry analysis. Proteinlevels of cell cycle regulators were assessed by western blotting.Results: Expression of K6W-ubiquitin in lens epithelial cellsprevented cell proliferation and specifically caused cell cycledelay/arrest in the G2/M phase. Consistent with the cell cycledelay/arrest in the G2/M phase, typical substrates of theubiquitin-proteasome pathway and also M phase regulators such as cyclinA, cyclin B, and securin were stabilized by expression of K6W-ubiquitin.Cell cycle-dependent degradation of G1 phase regulators, such asthe Cdk inhibitor p27KIP, was also inhibited by the expression ofK6W-ubiquitin.Conclusions: These data demonstrate that the ubiquitin proteasomepathway plays an important role in regulating lens epithelial cellproliferation. Expression of dominant negative K6W-ubiquitin inhibitslens cell proliferation by inhibiting the degradation of cell cycleregulators.

[学科分类] 生物化学/生物物理