====== Transforming growth factor beta signaling pathway ======

The [[Transforming growth factor beta]] [[signaling pathway]] is involved in many cellular processes in both the adult organism and the developing embryo including cell growth, cell differentiation, apoptosis, [[cellular homeostasis]] and other cellular functions. In spite of the wide range of cellular processes that the TGFβ signaling pathway regulates, the process is relatively simple. TGFβ superfamily ligands bind to a type II receptor, which recruits and phosphorylates a type I receptor. The type I receptor then phosphorylates receptor-regulated SMADs (R-SMADs) which can now bind the coSMAD SMAD4. R-SMAD/coSMAD complexes accumulate in the nucleus where they act as transcription factors and participate in the regulation of target gene expression.