Fig. 4

NDRG1 overexpression suppressed p21 ubiquitylation. a To examine the influence of NDRG1 overexpression on p21 stability, translation of the cells was arrested by treatment with cycloheximide (CHX). At various times after CHX addition, protein was extracted, and then total p21 was investigated using western blot analysis. GAPDH was used as an internal control. b The expression of p21 was examined after treatment with MG132, an inhibitor of the ubiquitin-proteasome system. c and d Western blots with anti-ubiquitin antibody showed p21 ubiquitylation level after NDRG1 overexpression and knockdown in both HCT116 and SW1116 cell lines