(A) Euc1 interacts with SUMO pathway proteins in a yeast two-hybrid (Y2H) assay. A Y2H reporter strain (PJ69-7a) was transformed with Gal4 DNA-binding domain (BD) and Gal4 activation domain (AD) fusion constructs in the indicated combinations. AD-SUMO-GG can be conjugated to SUMOylation substrates, while AD-SUMO-AA is conjugation-deficient. Cells were spotted on control media or selective media (- His) and grown for 3 and 6 days, respectively. 