A Sensitivity of the indicated mutants to 6-AU. All strains carried a URA3 plasmid, pRS316, and were spotted on SD-Ura with or without 6-AU (100 μg/ml); plates were incubated for 2-4 days at 30°C. ULP2 and ulp2(C624A) represent ulp2Δ::HIS3 cells containing either pRS314-ULP2-FLAG or pRS314-ulp2(C624A)-FLAG. 