Functional domains in the Met4 protein. (A). Functional domains in the Met4 protein: ACT (ac tivation d omain), IR (I nhibitory R egion), AUX (Aux iliary Region), BD (B asic D omain), LZ (L eucine Z ipper), UIM (U biquitin I nteracting M otif). Blue outlines functions associated with the domains. Green arrows point to cofactors interacting with the domains. Cofactors with a regulatory role are marked in green. DNA binding cofactors are marked in gray. Red horizontal arrows emphasize that new interactions could be created between cofactors when they bind to Met4. (B). Scheme illustrating dissociation of Met4 homodimers by SCFMet30. See text for details.