... include the MLL1 CXXC domain [22], a portion of the MLL1TAD bound to the KIX domain of the cAMPresponse element-binding (CREB) binding protein(CBP) [23], a peptide from the Win motif of MLL1bound ... WDR5.Consistent with a central role for the MLL1 Win motif in the interaction by WDR5, substitution of arginine3765 with alanine in MLL1 abolishes the interactionbetween MLL1 and WDR5 [25,36]. Furthermore, ... developed an in vitro system to examine the enzymatic activity and product specificity of the MLL1 SET domain in the presence and absence of MLL1-interacting proteins WDR5, RbBP5, Ash2L and DPY-30...