P63 (ΔN) is a member of the p53 family. This protein has multiple isoforms TA p63-α, -β, γ, ΔN p63-α, -β, and -γ. The molecular weights of the p63 isoforms α=66 kD, β=52 kD, and γ=45 kD. This nuclear protein is essential for limb formation, epidermal morphogenesis, and epithelial stem cell regeneration. δN isoforms are antagonistic to p53, TA isoforms can transactivate p53 targets. The p63 ΔN isoforms repress TA isoforms, mutant p53 abrogates p63 transactivation. This protein interacts with p53, p73, and the various TA- and ΔN isoforms. The Poly6190 antibody recognizes human p63 ΔN isoforms and has been shown to be useful for Western blotting.