TAX1BP3 (Tax1 binding protein 3) is a PDZ domain-containing protein that regulates multiple cellular processes through protein-protein interactions and nucleocytoplasmic shuttling. The protein undergoes SUMOylation at lysine 116, which is essential for its nuclear localization and shuttling between cellular compartments during phenotypic transitions 1. TAX1BP3 functions as a negative regulator of the YAP-TEAD signaling pathway by competitively binding to YAP through its TEAD binding domain, thereby controlling cell cycle progression and proliferation 1. The protein plays critical roles in cardiovascular development and disease, with mutations causing dilated cardiomyopathy and septo-optic dysplasia through impaired protein structure and stability 2. In arrhythmogenic cardiomyopathy, TAX1BP3 deficiency leads to TRPV4-mediated calcium leak from ryanodine receptors, resulting in delayed afterdepolarizations and increased arrhythmia susceptibility 3. TAX1BP3 also translocates to the plasma membrane following ionizing radiation exposure, serving as a biomarker of tumor radiosensitivity 4. Additionally, the protein has been implicated as a prognostic marker in melanoma immunotherapy response 5 and heart failure pathogenesis 6, highlighting its diverse roles in cellular stress responses and disease progression.