Plasma membrane repair defects cause human muscle and heart diseases. In the early stage of membrane repair, TRIM72/MG53 nucleates vesicles to the damaged site within seconds. Despite the therapeutic potential of TRIM72/MG53, the molecular mechanisms are poorly understood. Here, we present the structure of TRIM72, the first complete model of a TRIM E3 ligase. Structure-guided functional analysis revealed a unique phospholipid recognition mode in which a pair of PRYSPRY domains interacts with negatively charged membranes. In subsequent biochemical analyses, the interaction between TRIM72 and the phosphatidylserine-enriched membrane was shown to be critical for both the oligomeric assembly and ubiquitination activity of TRIM72. We elucidated a higher-order model of TRIM72 assembly on the phospholipid bilayer using cryogenic electron tomography followed by subtomogram averaging. We developed a working molecular model of TRIM72 through integrated structural and biochemical techniques. The findings provide a fundamental basis for the study of TRIM E3 ligases, which share a conserved molecular architecture, and provide further insights into the general regulation of RING-type E3 ligases through the cooperation of multiple domains like those in higher-order assemblies.