May have E3 ubiquitin-protein ligase activity (By similarity). Regulator of Src-induced anchorage independent cell growth. S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + N(6)-ubiquitinyl-[acceptor protein]-L-lysine. Protein modification; protein ubiquitination. Homodimer (By similarity). Interacts with isoform p52shc of SHC1. Predomintanly expressed in the cytoplasm but a fraction is associated with the mitochondria. Highly expressed in the gastrointestrinal tract, with high expression in the small intestine, moderate in the large intestine and weak in the stomach and esophagus. Auto-ubiquitinated (in vitro).