Component of cohesin complex, a complex 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 anaphase, the rad21 subunit of the cohesin complex is cleaved and dissociates from chromatin, allowing sister chromatids to segregate. The cohesin complex may also play a role in spindle pole assembly during mitosis. Cohesin complexes are composed of the psm1/smc1 and psm3/smc3 heterodimer attached via their hinge domain, rad21/scc1 which link them, and psc3/scc3, which interacts with rad21. Interacts with swi6 (By similarity). The interaction with swi6 may contribute to recruit cohesin complex to heterochromatin. Associates with chromatin. Cohesin complex mainly associates with broad centromere region. Also associates with mating-type heterochromatic region. Belongs to the SCC3 family.