DeltaN p63 (ΔNp63) is a major protein isoform encoded by the TP63 gene. The TP63 gene is a member of the p53 gene family, which also includes p53 and p73. The key defining feature of DeltaN p63 (ΔNp63) is the absence of the full N-terminal transactivation domain. However, it retains the central DNA-binding domain (DBD) and the C-terminal oligomerization domain (OD). The α-isoform also has a sterile alpha motif (SAM) domain and a transcriptional inhibitory domain (TID). DeltaN p63 isoforms can act as dominant-negative inhibitors of p53 and TAp63 by competing for DNA binding sites or forming non-functional dimers. DeltaN p63 is highly expressed in basal layers of epithelial tissues and is essential for the maintenance and proliferation of epithelial stem cells. It plays a pivotal role in epidermal development, stratification, and regeneration.