E3 (ubiquitin) ligases interact with both ubiquitin-E2 (ubiquitin-conjugating) enzymes and the target protein, transferring the ubiquitin from the E2 to the substrate. The Goliath (or GRAIL) E3 ligases possess transmembrane spanning domain, a protease-associated domain and a RING finger domain. (Adapted from
FBrf0220873).