Function
SMAD4 binds to receptor-regulated SMADs (R-SMADs), such as SMAD1 or SMAD2 and facilitates the translocation of the heteromeric complex into the nucleus. SMAD4 may form heterotrimeric, heterohexameric or heterodimeric complexes with R-SMADs.
In the nucleus the heteromeric complex binds promoters and interact with transcriptional activators. SMAD3/SMAD4 complexes can directly bind the SBE (Smad-binding DNA element), which is a four-base-pair sequence 5′-GTCT-3' or the complement 5′-AGAC-3′. These associations are weak and require additional transcription factors such as members of the AP-1 family, TFE3 and FoxG1 to regulate gene expression.
Many TGFβ ligands use this pathway and subsequently SMAD4 is involved in many cell functions such as differentiation, apoptosis, gastrulation, embryonic development and the cell cycle.
Read more about this topic: Mothers Against Decapentaplegic Homolog 4
Famous quotes containing the word function:
“To look backward for a while is to refresh the eye, to restore it, and to render it the more fit for its prime function of looking forward.”
—Margaret Fairless Barber (1869–1901)
“My function in life is not to be a politician in Parliament: it is to get something done.”
—Bernadette Devlin (b. 1947)
“We are thus able to distinguish thinking as the function which is to a large extent linguistic.”
—Benjamin Lee Whorf (1897–1934)