Cleavable component of the cohesin complex; involved in chromosome cohesion during cell cycle. The cohesin complex is required for the cohesion of sister chromatids after DNA replication. The cohesin complex apparently forms a large proteinaceous ring within which sister chromatids can be trapped. At metaphase-anaphase transition; this protein is cleaved by cut1 and dissociates from chromatin; allowing sister chromatids to segregate. Also involved in the DNA double-strand-break (DSB) repair system. {ECO:0000269|PubMed:11069892; ECO:0000269|PubMed:1480481}.