SAM (sterile alpha motif) domain of CP2-like transcription factor is a putative protein-protein interaction domain. Proteins of this group have an N-terminal DNA-binding CP2 domain, a central predicted SAM domain and some also have a C-terminal dimerization domain. CP2-like family of transcriptional factors includes three subgroups: LBP1, TFCP2, and LBP9. Members of this family are involved in transcriptional regulation from early development to terminal differentiation. They play a role in regulation of expression of P450scc (the cholesterol side-chain cleavage enzyme, cytochrome) in placenta, and alpha-globin in erythroid cells. They are required for proper maturation of the dust (epithelial component of tubular organs) of kidney and salivary gland. Human LBP1 is known to be induced by HIV type I infection in lymphocytes; it represses HIV transcription by preventing the binding of TFIID to the virus promoter. Additionally, it has been suggested that UBP1 (LBP1) regulator might be a member of a blood pressure controlling network. LBP1 protein isoforms are able to form dimers apparently via SAM domain since SAM deletion or mutation resulted in a loss of this ability.
Jiyao W et al.(2023). "The conserved domain database in 2023.",