Immunoblotting was performed with rabbit anti-WWP1 antibodies (1 : 700, ab43791; Abcam), and anti-GAPDH antibodies (1 : 1000, ab8245; Abcam) were used as an internal loading control. Membranes were washed and incubated with anti-rabbit IgG horseradish peroxidase-linked antibodies (7074; Cell Signaling Technology, Danvers, MA, USA). Complexes were visualised with Clarity Western ECL Substrate (Bio-Rad, Hercules, CA, USA), as described in our previous studies (Goto et al, 2014a (link); Goto et al, 2015a (link); Kurozumi et al, 2016 (link)).