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 make us feel small in the right way is a function of art; men can only make us feel small in the wrong way.”
—E.M. (Edward Morgan)
“Nobody seriously questions the principle that it is the function of mass culture to maintain public morale, and certainly nobody in the mass audience objects to having his morale maintained.”
—Robert Warshow (1917–1955)