Plays a central role in chromosome cohesion during mitosis and meiosis divisions by preventing premature dissociation of cohesin complex from centromeres after prophase; when most of cohesin complex dissociates from chromosomes arms. Probably act by protecting REC8 and RAD21 from separase degradation during anaphase. Also acts as a spindle checkpoint component required for sensing tension between sister chromatids during mitosis; its degradation when they separate preventing cell cycle arrest and chromosome loss in anaphase; a time when sister chromatids are no longer under tension. {ECO:0000269|PubMed:14752166; ECO:0000269|PubMed:15062096; ECO:0000269|PubMed:15637284}.