CRM1 (chromosome region maintenance 1, also known as exportin-1 or XPO1), a member of the karyopherin β family of transport receptors, is an important nuclear export receptor recognizing proteins bearing a leucine-rich nuclear export signal (PMID: 9323133). CRM1 is the major receptor for the export of proteins out of the nucleus and is also required for transport of many RNAs (PMID: 17317185). In addition to nuclear export, CRM1 also plays a role in centrosome duplication and spindle assembly (PMID: 22773955).