SAM (sterile alpha motif) domain of p63, p73 transcriptional factors is a putative protein-protein interaction domain and lipid-binding domain. p63 and p73 are homologs to the tumor suppressor p53. They have a C-terminal SAM domain in their longest spliced alpha forms, while p53 doesn't have it. p63 or p73 knockout mice show significant developmental abnormalities but no increased cancer susceptibility, suggesting that p63 and p73 play a role in regulation of normal development. It was shown that SAM domain of p73 is able to bind some membrane lipids. The structural rearrangements in SAM are necessary to accomplish the binding. No evidence for homooligomerization through SAM domains was found for p63/p73 subfamily. It was suggested that the partner proteins should be either more distantly related SAM-containing domain proteins or proteins without the SAM domain.
Jiyao W et al.(2023). "The conserved domain database in 2023.",