Different domains regulate homomeric and heteromeric complex formation among type I and type II transforming growth factor-beta receptors.

Transforming growth factor-beta (TGF-beta) binds to and signals via two serine-threonine kinase receptors, type I (TbetaRI) and type II (TbetaRII). The oligomerization of TGF-beta receptors modulates ligand binding and receptor trafficking and may contribute to signal diversification. However, numerous features of the molecular domains that determine the homo- and hetero-oligomerization of full-length receptors at the cell surface and the mode of these interactions remain unclear.