E3 ubiquitin-protein ligase that acts as a negative regulator of BMP signaling pathway. Mediates ubiquitination and degradation of SMAD1 and SMAD5, 2 receptor-regulated SMADs specific for the BMP pathway. Promotes ubiquitination and subsequent proteasomal degradation of TRAF family members and RHOA. Interacts with TRAF4. Interacts (via HECT domain) with FBXL15 (via LRR repeats). Interacts with SMAD7 and TGFBR1; SMAD7 recruits SMURF1 to TGFBR1 and regulates TGF-beta receptor degradation. 2 isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.
SS: The number of records in which this modification site was determined using site-specific methods. SS methods include amino acid sequencing, site-directed mutagenesis, modification site-specific antibodies, specific MS strategies, etc.