Ran is a member of the Ras family of small GTPases. The Ran subgroup is represented by its lone member, Ran, that is distinguished from Ras GTPases by its lipid modification and atypical subcellular localization. Unlike most other Ras-related proteins, Ran is not modified to bind to cell membranes. Instead, Ran protein is localized throughout the cell, where it is concentrated primarily in the nucleus (Ref.1). Ran is regulated by a cytosolic RanGAP1 (Ran GTPase–Activating Protein-1) and by a RanGEF (Chromatin-Bound Guanine Nucleotide Exchange Factor). The distribution of RanGTP provides important spatial information that directs cellular activities during different parts of the cell cycle. During interphase, the localization of RanGEF and RanGAP1 predicts that nuclear Ran is GTP-bound and cytosolic [...]