Fig. 5

NDRG1 could emulatively antagonize NEDD4-mediated ubiquitylation of p21. a and (b) Using UbiBrowser Database (http://ubibrowser.ncpsb.org/), we screened possible E3 ligases related to NDRG1 or p21. c p21 expression increased after NEDD4 knockdown by si-RNA-NEDD4. d Co-immunoprecipitation was performed to examine whether p21 interacted with NEDD4 in both HCT116 and SW1116 cell lines. e Immunofluorescence co-localization assay was used to further confirm that p21 interacted with NEDD4 (red: NEDD4, green: p21, blue: DAPI, scale bar: 5 μm). f NEDD4 expression was not influenced by NDRG1 expression. g and (h) Co-immunoprecipitation was used to detect the changes in combination between p21 and NEDD4 after NDRG1 overexpression and knockdown