New insights into extracellular and post-translational regulation of TGF-β family signalling pathways.

Members of the transforming growth factor-β (TGF-β) family of secreted proteins
are present in all multicellular animals. TGF-β proteins are versatile
intercellular signalling molecules that orchestrate cell fate decisions during
development and maintain homeostasis in adults. The Smad family of signal
transducers implements TGF-β signals in responsive cells. Given the ability of
TGF-β ligands to induce dramatic responses in target cells, numerous regulatory
mechanisms exist to prevent unintended consequences. Here we review new reports
of extracellular and post-translational regulation in Drosophila and vertebrates.
Extracellular topics include the regulation of TGF-β signalling range and the
coordination between tissue morphogenesis and TGF-β signalling.
Post-translational topics include the regulation of TGF-β signal transduction by
Gsk3-β phosphorylation of Smads and by cycles of Smad mono- and deubiquitylation.
Extension of the ubiquitylation data to the Hippo pathway is also discussed.