| An RNF 11 : Smurf 2 complex mediates ubiquitination of the AMSH protein . ^^^ Our results also demonstrate that AMSH is ubiquitinated by Smurf 2 E3 ligase in the presence of RNF 11 and that a consequent reduction in its steady state level requires both RNF 11 and Smurf 2 . ^^^ RNF 11 therefore recruits AMSH to Smurf 2 for ubiquitination , leading to its degradation by the 26S proteasome . ^^^ |