Predicted to enable ubiquitin-ubiquitin ligase activity. Predicted to be involved in protein ubiquitination and ubiquitin-dependent protein catabolic process. Predicted to be part of ubiquitin ligase complex. Is an ortholog of C. elegans ufd-2. In C. elegans, ufd-2 is involved in determination of adult lifespan; positive regulation of proteasomal ubiquitin-dependent protein catabolic process; and protein ubiquitination.