SMAD2 and fibrosis: We did not observe any difference at the mRNA level of SMAD2 in WWP2Mut/Mut cardiac (myo)fibroblasts or in cells overexpressing or silencing the WWP2-N/FL isoforms (Supplementary Fig. 11b, c), suggesting that WWP2 function on cardiac fibrosis could be exerted through SMAD2 interaction and ubiquitination at the protein level.