Fig. 1

NEDD4 through its WW domain 4 binds to IGPR-1. a A schematic of IGPR-1 and the locations of the poly-proline rich motifs at the C-terminus. b Schematic of NEED4 domains and GST constructs corresponding to WW domains (#1,3,4). c Coomassie blue staining of purified GST-NEDD4 fusion WW domains. d HEK-293 cells expressing empty vector (EV) or IGPR-1-Myc were subjected to an in vitro GST-pull-down assay corresponding to WW domains (1, 3 and 4) of NEDD4, followed by Western blot analysis using an anti-IGPR-1 antibody. The same membrane was blotted with an anti-GST antibody for GST-NEDD4 fusion proteins. e Western blot analysis of whole cell lysate of HEK-293 cells expressing EV or IGPR-1-Myc immunoblotted for IGPR-1 or GAPDH. f HEK-293 cells expressing EV or IGPR-1-Myc were transfected with NEDD4-HA. After 48 h post-transfection, cells were lysed and subjected to co-immunoprecipitation assay via anti-IGPR-1 antibody followed by Western blot analysis using HA antibody. The membrane was re-blotted with anti-IGPR-1 antibody. Whole cell lysate (WCL)