C2, calcium-binding domain; WW, tryptophan - tryptophan (WW) domain; HECT, homologous to the E6-AP carboxyl terminus (HECT) domain. NEDD4, neuronal precursor cell-expressed developmentally downregulated 4; NEDD4L, NEDD4 like E3 ubiquitin protein ligase; ITCH, itchy E3 ubiquitin protein ligase; WWP1, WW domain containing E3 ubiquitin protein ligase 1; WWP2, WV, domain containing E3 ubiquitin protein ligase 2; SMURF1, SMAD specific E3 ubiquitin protein ligase 1; SMURF2, SMAD specific E3 ubiquitin protein ligase 2; HUWE1, HECT, UBA and WWE domain containing E3 ubiquitin protein ligase 1; HUWE2, HECT, UBA and WWE domain containing E3 ubiquitin protein ligase 2.