Finale: the Last Minutes of Smads

TGF-beta ligands induce phosphorylation of receptor-activated Smads at both the C-terminal tail and the linker region. Two papers from Massagué and colleagues (Alarcón et al., 2009; Gao et al., 2009) reveal a dual role for this linker phosphorylation, which is required for activation of Smads and for their degradation.