Acetyltransferase required for sister chromatid cohesion; elicits cohesin dimerization during S phase; acetylates Mps3p to regulate nuclear organization; modifies Smc3p at replication forks and Mcd1p in response to dsDNA breaks; phosphorylated by Cdc28p, Cdc7p, Mck1p to generate pair of phosphates spaced precisely for recognition by ubiquitin ligase SCF-Cdc4; relative distribution to nucleus increases upon DNA replication stress; mutations in human homolog ESCO2 cause Roberts syndrome