(A) Euc1 Slx5-binding mutations impair Euc1 ubiquitylation. His-ubiquitin-modified proteins were enriched by denaturing NiNTA-PDs as described in Fig. 4E. 3FLAG-tagged Euc1 constructs were expressed from plasmids under the control of the ADH promoter. NiNTA-PD eluates were probed with FLAG and ubiquitin (P4D1) antibodies. Whole cell lysates (input) were probed with FLAG and Dpm1 antibodies. 