Fig. 2. Functional domains of p53 family proteins. The transactivation (TA), DNA binding (DBD), oligomerization (OD), SAM, and proline-rich (PR) domains are shown for each of the family members. Alternative splice p53 undergoes splicing, which results in a replacement of p53 amino acids 364–390 with 17 unique amino acids. Alternative splicing of p73 and p63 mRNA (depicted in Fig. 1 ) leads to different COOH termini. These forms are identical through the end of the OD region. Unique coding sequences are represented as different diagonal and vertical striped patterns. The {Delta}Np73 and {Delta}Np63 forms lack the TA domain and contain unique NH2-terminal amino acids (represented by the shaded {Delta}N box) not found in the TA-containing forms. The asterisk located on p63 refers to a caspase recognition sequence, YVED. The entire SAM domain is present only in the {alpha} forms of p73 and p63.