Structural maintenance of chromosomes protein 1A (SMC1A) is a homologue of the yeast Smc1 protein, which is a component of the cohesin complex required for sister chromatid cohesion []. In human, it is part of the core cohesion complex composed of SMC1A, SMC3, RAD21 and STAG proteins []. These proteins form a ring structure that encircles sister chromatids to mediate sister chromatid cohesion []. SMC1A binds to SMC3 through its hinge domain []. Besides sister chromatid cohesion function, SMC1A-SMC3 heterodimer can also found in the RC-1 complex, a mammalian protein complex that promotes repair of DNA gaps and deletions through recombination [, ]. This entry also includes Smc1 homologue from Caenorhabditis elegans, SMCL-1. Unlike canonical SMC proteins, SMCL-1 lacks hinge and coil domains, and its ATPase domain lacks conserved amino acids required for ATP hydrolysis []. Mutations in SMC1A gene cause Cornelia de Lange syndrome 2 (CDLS2), which is a form of Cornelia de Lange syndrome, a clinically heterogeneous developmental disorder associated with malformations affecting multiple systems [, ].
