Research Paper Volume 1, Issue 5 pp 490—502

Figure 2. Linear Peptide Docking Sites in p53. (A) Linear peptide docking sites for enzymes that regulate p53 function. The N-terminus is composed of three transactivation motifs,TAD1, TAD2, and Proline-repeat domain (PRD). A key regulatory domain in the C-terminus (REG) contains the acetylation motifs and phosphorylation site and flanks the Tetramerization domain (TET). The overlapping, but distinct, linear polypeptide docking motifs for p53 regulators include the acetyltransferase p300, the E3 ubiquitin ligase MDM2, iASPP, and the protein kinases including CDK, CK2, CK1, and CHK2 are highlighted. (B) Conservation of key phospho-acceptor sites between urochordate and human. The panel highlights the conservation of amino acids and phospho-acceptor sites in the BOX-I transactivation domain of p53 (TAD1 in Figure 2A) between human and urochordate (Ciona intestinalis). The ATM phospho-acceptor site at Ser15 and the Calcium Calmodulin kinase/CK1 phospho-acceptors sites at Thr18 and Ser20 are highlighted as indicated.