SAM (sterile alpha motif) domain of p73 proteins is a putative protein-protein interaction and lipid-binding domain. p73 is a homolog to the tumor suppressor p53. p73 has a C-terminal SAM domain in the longest spliced alpha form, while p53 doesn't have it. p73 knockout mouse shows significant developmental abnormalities but no increased cancer susceptibility, suggesting that p73 plays 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 the 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.",