Differential ubiquitination defines the functional status of the tumor suppressor Smad4

Morén A, Hellman U, Inada Y, Imamura T, Heldin CH, Moustakas A.
J Biol Chem. 2003 Aug 29;278(35):33571-82. Epub 2003 Jun 5.
PMID:12794086 DOI:10.1074/jbc.M300159200