Cohesins

Synonyms

Cancer; Cohesin; Cohesin pathway dysregulation; Gene mutations

Definition

Cohesin is a chromosome-associated multi-subunit protein complex that is evolutionarily conserved from yeast to humans. In mammalian cells, the mitotic cohesin core complex consists of four proteins, SMC1A, SMC3, RAD21, and either STAG1 or STAG2. SMC proteins are members of the “Structural Maintenance of Chromosomes” (SMC) family whose members are large ATPases with a peculiar domain organization. In fact, they contain two coiled coil domains separated by a flexible globular hinge domain (Fig. 1a). The hinge domains of SMC1A and SMC3 interact with each other to create a heterodimer, while their head domains connect with RAD21, forming a closed ring-like structure. Finally, the RAD21 subunit associates with STAG (Fig. 1b). Meiotic isoforms of cohesin core subunits also exist. In mammals, SMC1A and STAG1/STAG2 can be replaced by SMC1B and STAG3, respectively. In addition, in germinal cells, RAD21 is...