Mec1-Dependent Phosphorylation of the Scc3 Subunit of Cohesin during Mitosis in Budding Yeast

International audience ; Cohesin is an evolutionary conserved complex that controls chromosome segregation during mi-tosis. Here we show that, in response to DNA damage, Saccharomyces cerevisiae Scc3, one of the major regulatory subunits of the Smc1-Smc3-Scc1 cohesin ring, is phosphorylated on S/T-Q residues. This event depended on the Mec1 checkpoint kinase as well as on cell cycle arrest triggered by the DNA damage checkpoint network. This phosphorylation event also took place during mito-sis of an unperturbed cell cycle. The present finding that S. cerevisiae Scc3 is phosphorylated during mitosis represents a potentially important new regulatory step in cohesin's mitotic functions.