TNFAIP1 (TNF alpha induced protein 1) functions as a substrate-specific adapter protein in BCR (BTB-CUL3-RBX1) E3 ubiquitin-protein ligase complexes that regulate cytoskeletal structure and cell migration through targeted protein degradation 1. The protein mediates K48-linked polyubiquitination of specific substrates, including SNAP25 at lysine 69, leading to their proteasomal degradation 1. TNFAIP1 acts as a tumor suppressor in multiple cancer types, with downregulated expression observed in uterine, gastric, pancreatic, and osteosarcoma cancers 2345. The gene is regulated by oncogenic microRNAs including miR-373, miR-181a, and miR-15a, which target TNFAIP1 mRNA and promote tumorigenesis 345. In neurological contexts, TNFAIP1 upregulation contributes to postoperative cognitive dysfunction by promoting SNAP25 degradation, impairing mitophagy and inducing pyroptosis 1. During development, tnfaip1 is essential for proper embryonic development, particularly neuronal development and eye formation 6. Transcriptional regulation involves Sp1 binding sites in the promoter region 7.