Cohesin/condensin contain structural maintenance of chromosomes (Smc) family of chromosomal ATPases, and non-Smc participants.

In Hltf null brain, the functional architecture of each complex is jeopardized by reduced availability (pale shading) of transcripts for major protein components. Panel A, Two twisted Smc proteins (Smc1 and Smc3) that generate V-shaped heterodimers via their hinge domains comprise the core of cohesin. The association of the N- and C-termini of Smc1 and Smc3 with Rad21/Scc1, a kleisin family member that controls separation of sister-chromatids, completes the tripartite ring-like structure. Once properly placed, Rad21/Scc1 is joined at its C-terminus by Stag1 (Scc3). Panel B, Smc2 and Smc4 form V-shaped heterodimers via their hinge domains, and Cap-H/H2, kleisin family members, completes the tripartite ring-like structure. In addition to Cap-H, Condensin I has two additional non-Smc subunits (Cap-D2 and Cap-G). In addition to Cap-H2, Condensin II has Cap-D3 and Cap-G2.