Activation of ATM signaling pathway by ectopic expression of NPRL2 protein.

(A), Effects of ectopic expression of NPRL2 on expression and phosphorylation of ATM and NBS1 proteins.H1229 cells treated with an empty vector (EV) vector and IC20 dose of cisplatin (3.0 µM), NPRL2, or NPRL2 and IC20 dose of cisplatin were harvested at 24, 48, and 72 h after treatment and analyzed for expression of ataxia telangiectasia mutated (ATM) kinase, phospho-ATM (Ser1981), NBS1, and phospho-NBS1 (Ser343). β-actin was used as a loading control. Increases in phospho-ATM and phospho-NBS1 were observed in cells treated with NPRL2 or NPRL2 and cisplatin in a time-dependent manner, but not in cells treated with the control empty vector and cisplatin. (B), Effects of NPRL2-specific siRNA (Si) on expression of NPRL2 and ATM proteins in the presence and absence of cisplatin (CDDP). The scrambled siRNA (Sc) was used as a non-specific control.