. "\"The chemical reactions and pathways resulting in the breakdown of SMAD signaling proteins by ubiquitination and targeting to the proteasome.\" [GOC:go_curators]" . . "ubiquitin-dependent SMAD protein catabolic process" . "ubiquitin-dependent SMAD protein breakdown" . "ubiquitin-dependent SMAD protein catabolism" . "ubiquitin-dependent SMAD protein degradation" . .