Enables SMAD binding activity. Predicted to be involved in cellular protein metabolic process; positive regulation of transcription, DNA-templated; and positive regulation of transforming growth factor beta receptor signaling pathway. Predicted to act upstream of or within pattern specification process; positive regulation of protein ubiquitination; and protein polyubiquitination. Predicted to be located in cytosol and nucleoplasm. Predicted to be part of protein-containing complex. Predicted to be active in cytoplasm and nucleus. Orthologous to human RNF111 (ring finger protein 111). [provided by Alliance of Genome Resources, Apr 2022]