Structural Maintenance of Chromosomes (SMC) proteins are a family of ATPases involved in chromosome organization and are critical to genome stability and maintenance. Three distinct SMC-containing complexes (cohesin, condensin and Smc5/6) have been identified in eukaryotes, each containing a specific SMC heterodimer plus specific non-SMC regulatory subunits. (Adapted from FBrf0225012 and FBrf0218078).