In S. cerevisiae, Pds1p (also known as securin) regulates sister chromatids cohesion, because it binds and inhibits the protease Esp1p (separin or separase).
According to some observations, a fraction of cohesins in the chromosomal arms and the centromeric cohesins are protected by the protein Shugoshin (Sgo1), avoiding their release during prophase [REF].