part of chromosome cohesin complex 14S cohesin GO:0043222 nuclear cohesin complex cellular_component GO:0008278 SMC/kleisin ring complex GO:0008279 GO:0000798 cohesin core heterodimer Smc1-Smc3 complex 9S cohesin GO:0008280 A protein complex that is required for sister chromatid cohesion in eukaryotes. The cohesin complex forms a molecular ring complex, and is composed of structural maintenance of chromosomes (SMC) and kleisin proteins. For example, in yeast, the complex is composed of the SMC proteins Smc1p and Smc3p, and the kleisin protein Scc1p. In vertebrates, the complex is composed of the SMC1 (SMC1A or SMC1B) and SMC3 heterodimer attached via their hinge domains to a kleisin (RAD21, REC8 or RAD21L) which links them, and one STAG protein (STAG1, STAG2 or STAG3). SMC complex protein-containing complex