NEDD4 (neuronal precursor cell expressed developmentally downregulated 4) is an E3 ubiquitin ligase that plays crucial roles in protein degradation and cellular regulation through substrate ubiquitination 1. The protein functions by recognizing target proteins via its WW domain and catalyzing their ubiquitination, leading to proteasomal degradation 2. NEDD4 regulates diverse cellular processes including cell proliferation, apoptosis, migration, and ion transport 1. Key mechanistic examples include NEDD4-mediated ubiquitination of GSNOR in cardiac hypertrophy 3, VDAC2/3 degradation in ferroptosis resistance 4, and TAK1 ubiquitination in trophoblast necroptosis 5. NEDD4 shows significant disease relevance across multiple systems. In cardiovascular disease, it contributes to cardiac hypertrophy, heart failure, hypertension, and arrhythmias by targeting proteins like GSNOR, ENaC, and Nav1.5 32. In cancer, NEDD4 exhibits context-dependent roles, promoting ferroptosis resistance in melanoma 4 while showing varied expression patterns in breast cancer 6. Clinically, NEDD4 represents a promising therapeutic target, with inhibitors like indole-3-carbinol currently in phase II clinical trials showing efficacy against cardiac hypertrophy 3. The protein's broad substrate specificity and involvement in multiple disease pathways make it an attractive candidate for drug development 1.