OPEN ACCESS JOURNAL AT INIST-CNRS Cohesins and cohesin-regulators: Role in Chromosome Segregation/Repair and Potential in

Cohesin is the name of a multifunctional protein complex, which was initially discovered and characterized by its role in maintain cohered sister chromatids during chromosome segregation in cell division. However, in the last years a large number of studies and results have evidenced the implication of cohesin complexes in different crucial processes in cell life such as DNA replication, control of gene expression, heterochromatin formation, and DNA-repair. The canonical cohesin complex consists in four subunits named SMC1, SMC3 (Structural Maintenance of Chromosomes) and SCC1, SCC3 (Sister Chromatid Cohesion). Two last subunits have also denominated RAD21 for SCC1 and STAG for SCC3 in mammals. These four subunits, named also cohesin individually, are able to form a ring-like structure (figure 1A), which could modulate different local chromatin conformations depending on the interactions with diverse cohesin-interacting proteins, which have been designated as cohesin cofactors and/or cohesin-regulators. Chromosomal instability is one of the hallmarks of cancer, generating chromosomic aberrations including aneuploidy, loss of heterozygosity, chromosomal translocations etc. Mutations in genes encoding for proteins that control cell cycle are potential candidates in the generation of genome instability. Thus, cohesins and cohesin-regulators, which are ke