SMC proteins are involved in:
Structural Maintenance of Chromosomes proteins represent large ATPase machines forming elongated coiled-coil dimers with hinge domain closing ring-like structures embracing DNA duplexes. Condensin complexes SMC2/SMC4 compact mitotic chromosomes via loop extrusion, cohesin SMC1/SMC3 holds sister chromatids together from S phase until anaphase cleavage by separase, SMC5/SMC6 aids homologous recombination repair at collapsed forks. Mutations produce chromosome missegregation, aneuploidy and repair defects. Proteins localize to scaffold attachment regions and utilize ATP hydrolysis to extrude loop
Ref: Hirano T 2016 Nat Rev Mol Cell Biol SMC; Lodish et al., Chapter 19: SMC Proteins Chromosome Maintenance