Cand1 (Cullin-associated and neddylation-dissociated protein 1)has long been known as a regulator of SCF ubiquitin iigases,but details remained puzzling due to conflicting results from in vitro and in vivo experiments.Three recent reports,one in Cell and two in Nature Communications,propose Cand1 as a protein exchange factor with interesting mechanism that reconciles Cand1genetics and biochemistry.