New insights into TGF-β–Smad signalling

Transforming growth factor β (TGF-β) initiates its diverse cellular responses by binding to and activating specific cell surface receptors that have intrinsic serine/threonine kinase activity. These activated TGF-β receptors stimulate the phosphorylation of receptor-regulated Smad proteins, which in turn form complexes with Smad4 that accumulate in the nucleus and regulate the transcription of target genes. TGF-β responses can be cell-type...