Figure 2.

Subunit organization of cohesin and condensins. Cohesin is composed of a dimer of SMC1 and SMC3, a kleisin subunit (Rad21/Scc1), and a HEAT (Huntingtin, elongation factor 3, A subunit of protein phosphatase 2A, TOR)-repeat subunit (SA/Scc3). Condensin I and II share the same pair of SMC2 and SMC4, and contain distinct sets of non-SMC regulatory subunits; each set is composed of a single kleisin subunit (CAP-H for condensin I; CAP-H2 for condensin II) and a pair of HEAT-repeat subunits (CAP-D2 and CAP-G for condensin I; CAP-D3 and CAP-G2 for condensin II). The cohesin complex is further regulated by loosely associated factors, such as Wapl-Pds5 and sororin.